Cops and robbers
Different societies have different approaches to policing.
The traditional British model is "policing by consent" (of the general public) and not "policing by force". Ordinarily,
policemen don't carry firearms in Britain, though it's becoming slightly more commonplace to see armed officers from trained police services
on special duties.
Rather impractical in modern times, the traditional "Bobby's" uniform with its blue tunic is mostly defunct, while the famed, high-rise "custodian" helmets are seen less often and viewed by some police services as unsuitable, formal uniform only being worn for ceremonial occasions or by desk-bound senior officers (who wear caps anyway). Most officers are now seen in either flat, peaked caps—or the familiar custodian helmets—but with body armour and hi-vis police vests, but no trousers.
Only kidding, they wear trousers.
Tactical teams wear appropriate fatigues/jumpsuits and equipment suitable for their duties, as well as baseball caps.
WPCs (Women Police Constables) are no longer called WPCs but PCs, like their male colleagues. They also wear trousers. No longer are they described by colleagues as "Doris" or "a plonk", as both terms are now (rightfully) regarded as derogatory and sexist.
In general, the police are polite and respectful of the citizens they serve, though recent events have shown them to be increasingly and worryingly politicised, while racism and misogyny remain persistent problems in London's Metropolitan Police force and some other regional constabularies.
On police ranks
Many modern designations of rank were originally instituted by Robert Peel, founder of the Metropolitan Police in the 19th Century. A Chief Constable is the head of any regional police force, except in the City of London Police and the Metropolitan Police who have a Commissioner, a Deputy Commissioner and an Assistant Commissioner as their leading three ranks. A Chief Constable is supported by a Deputy Chief Constable and an Assistant Chief Constable. Those two ranks are equivalent, in the Metropolitan Police, to Deputy Assistant Commissioner and Commander respectively. Below that, in all regions, there are the ranks of Chief Superintendent, Superintendent, Chief Inspector, Inspector, Sergeant and Constable. From Chief Superintendent downwards in rank, there are detective equivalents. Though not strictly police officers, the police also have (Police) Community Support Officers. They have some powers of a police constable but have no warrant, and are sometimes derisively referred to as "plastic policemen" by warranted officers. In addition, there are Special Constables—volunteer reservists attached to each regional force in Britain—who serve part time with full police powers. Often appearing in older cinema and TV dramatic representations are Traffic Wardens, who had limited powers to bestow penalties for illegal parking etc. The Wardens have almost all been replaced by outsourced Civil Enforcement Officers, with no police powers, employed by local authorities.
A DCS is a Detective Chief Superintendent; a DCI is a Detective Chief Inspector; a DI is a detective Inspector; a DS is a Detective Sergeant; a DC is a Detective Constable. I'm unsure if Detective superintendents share the same designation as a Detective Sergeant (DS), but it seems highly unlikely.
On British slang associated with policing and crime
The names "Bobbies" or "Peelers" (the first less frequently seen in modern times, the second now archaic), used as nicknames for police officers derive from the foundation of an organised, London-wide service in 1829 by the Home Secretary of the time, Robert Peel. Before that, night-watchmen, thief takers, militias and ordinary citizens were expected to guard against crime. Pre-dating Peel, in the 18th Century, novelist and magistrate Henry Fielding (known for writing Tom Jones, or [more fully] The History of Tom Jones, a Foundling) organised a small force of officers to apprehend villains and bring them to court. They were commonly called Bow Street runners, though the appellation was at the time held to be disrespectful by the force itself. The runners were later subsumed into Peel's Metropolitan Police.
Other common slang for police officers ranges from the offensive, mostly used by criminals, to less objectionable, but hardly flattering soubriquets. "Pigs" is obviously known on both sides of the Atlantic, though "the filth" or "the scum" I suspect are not. Other derivatives of the porcine variety are "bacon" and "gammon", though the latter has come to be more a derogatory epithet for people voting for Brexit in the 2016 referendum rather than police officers. A "pig pen" is, therefore, a police station (or "cop shop") in disrespectful parlance.
"The old Bill" is more difficult to pin down, with some claiming that the practice of early officers carrying copies of the legislative bill of parliament that granted them their authority is the origin, while others claim it's a consequence of London's 1950s emergency vehicles (including police cars) carrying number (license) plates beginning "BYL". There are other theories but, whichever is true, the name is in general use and was employed in the title of a successful soapy police procedural TV series, The Bill (1983-2010).
"Cop" or "copper" is also well known both sides of the pond. Again, there are various theories of the term's origin. Most plausible to me is the use of the term "cop", meaning to catch or capture (also found in expressions like "cop a load of that", "cop this", etc). Some credence is given by the expression often put in the mouths of British criminals being caught red-handed by police, who declaim "It's a fair cop" (I have rightfully been caught). It then makes sense that someone who catches (or cops) criminals is a copper.
"Rozzer(s)" is slang for a policeman or the police dating from the 19th Century. I don't know the origins of it and can't find any plausible story. Something to do with lobsters or pigs, depending on source, but both, I think, are unlikely. It regained common use in the 1970s, which probably explains why former Top Gear presenter James May was occasionally heard using the term: he's the right age.
"The fuzz" is another transatlantic term. Claims are made for the mispronunciation of "force" or "Feds". It's too obscure for me.
"The Law", on the other hand speaks for itself.
"Plod" is also relatively easy to explain. The (increasingly rare) sight of a police officer walking his beat, ie patrolling on foot, easily conjures the thought of plodding along, walking slowly in order to scrutinise his/her surroundings for criminal activity. Infantile British children's author, Enid Blyton, named the policeman in her Noddy stories as PC (Police Constable) Plod.
Historically, the police have been referred to as "beetles" or "beetle crushers" due to the heavy footwear early officers wore, "bluebottles" because of the colour of their uniforms (and bluebottles are also a type of fly thought particularly disgusting, making the term derogatory), "bizzies" or "bizzy lizzies" (especially in and around Liverpool), which perhaps came about because they were considered to be intrusive in other people's business, while "bogeys" I can only think relates to congealed mucus (US boogers), though I can't be certain. That leaves "blue meanies", used in 1960s British counter-culture, describing the police's "spoilsport" attitude to the prevailing interests of youth (and used as a name for the invaders of Pepperland in the Beatles' film Yellow Submarine), "Dibble", an obvious reference to the well-intentioned but dim cartoon cop in Hannah-Barbera's Top Cat, and "Lily Law" from the Polari slang of fairground workers (US carnival roustabouts), the pre-1960s gay community and others considered on the fringes of "polite" society at that time.
The police themselves have not been shy of applying slang terminology to their colleagues. An officer from the Boondocks is known to the Metropolitan Police as a "carrot", or "carrot cruncher". Detectives in plain clothes have referred to uniformed officers as "woodentops", the expression deriving from the cork linings of their custodian helmets, but obviously carrying (as all these terms do) a derogatory meaning. "Lid" makes a similar reference to uniformed officers wearing custodian helmets. Lastly, less tall officers are known as "laptops", ie the smaller version of a PC.
1970s TV Police show, The Sweeney, was replete with rhyming and other London slang. Although the various regions of Britain have widely different accents, dialects and slang (even over short distances), along with several other TV entertainments, the programme overcame confusion and popularized London slang countrywide.
The Sweeney
"Maverick" cops were largely unheard of in British television series at that time, with just about all portrayals featuring professional, by-the-book officers. Those who weren't were usually corrupt officers exposed in the narrative to take their punishment.
Britain's first genuinely Maverick Cop on TV must have been the legendary DI Jack Regan (played by John Thaw—who had earlier played a military police sergeant in the TV series Redcap (1964, so named for the military millinery worn) and went on to possibly greater success starring as the more sophisticated but somewhat curmudgeonly titular DCI in Inspector Morse (1987). He was joined in The Sweeney by the sadly recently deceased Dennis Waterman (as DS George Carter), who went on to play the character of Terry McCann, an honest but easily manipulated bodyguard for a less than scrupulous businessman in Minder (1979) and then former DS Gerry Standing in the later police procedural New Tricks (2004). Garfield Morgan, mentioned earlier, played DCI Frank Haskins. Remember those names for later. As well as previously unacceptable levels of violence, the show also occasionally included semi-nudity. It may all seem rather quaint in the 21st Century, but it was quite revolutionary in its day.
The Sweeney was, perhaps unsurprisingly for its tone and content, broadcast by ITV in the UK and not the BBC and was a more famous successor for Euston Films' earlier series Special Branch (1969), which had in its later seasons pioneered the still-not-common use of an entirely on-film method of production for British drama.
Special Branch is a division of the Metropolitan Police Force that is concerned with matters of national security, while the Flying Squad (the Sweeney) is a division concerned with violent and large-scale crime. Both exist in the real world and both TV series were a shift in the presentation and perceptions of the police in Britain. In later years, the non-fictional Flying Squad was criticised for its dubiously close links to criminals and for its own criminality: the outfit's commander was successfully prosecuted for corruption. The entire Metropolitan Police Service was dubbed "institutionally racist" after an enquiry into the conduct of their investigation into the murder of a black London teenager revealed the force to be seriously delinquent in that conduct.
However, the representation of officers as hard-drinking and somewhat "boisterous", with chaotic or disintegrating private lives due to their work, as well as the level of violence shown in The Sweeney, had a large and positive effect on viewers and the approval of members of the real-life squad. The show ran for four seasons, spawning two contemporary movies (1977's Sweeney! and 1978's Sweeney 2) and inspiring both another film (2012's Sweeney, starring Ray Winstone) and the character of conduct in the Police fantasy series Life on Mars (2006) and its sequel, Ashes to Ashes (2008). The Sweeney provoked the BBC into their own imitative series, Target, which quite rightly didn't last long, despite a decent cast.
I didn't see the programme often on first broadcast, but have subsequently caught up over the intervening years. It was a ground-breaking show with good performances throughout. If I had any criticisms, they would primarily be the over-use of old Jaguar cars as the transport of villains (the stunt drivers favoured them for their safety and reliability and I discover that the Jaguar driven by Thaw as Morse in his later TV series had been used previously in The Sweeney for stunts), the overuse of the same (or at the very least too similar) areas of waste ground for car chases and other climactic moments, an often too-short running time of about 50 minutes for each episode, and an extremely variable quality of incidental music—sometimes appropriate, sometimes not, and sometimes sounding like poor library music.
Many quotations from The Sweeney are legendary (and even Wikiquotes has a dedicated page). However, a glossary of slang with particular reference to a crimefighting environment would probably come in handy for any non-British viewers watching The Sweeney.
The best-known form is probably London rhyming slang (often referred to as "Cockney" rhyming slang, after the traditionally cheery inhabitants of the East End of London. More accurately, its use is widespread throughout London and, through cultural appropriation, beyond). Popular television programmes, like The Sweeney have ensured its understanding, adoption and development in the wider UK.
Rhyming slang usually omits the rhyming, second component that connects the expression to its meaning. Obviously, this is a useful ploy for engaging in criminal or other secretive activity, providing those who are meant to be excluded don't know the code, and those who are meant to be included do know it. An example would be the use of "trouble" to denote a female spouse: "trouble and strife" = wife. Other forms of slang might also come into play, like Polari, in common use until the 1960s with fairground folk, theatricals and the gay community.
Glossary
Aristotle: rhyming slang for more rhyming slang—"bottle" (see below). Often abbreviated, as in "don't just sit on your 'Aris' all day. Go and do something".
Banged up: to be in prison
Battenburg: a police car with a chequered livery, resembling the pattern of the said baked comestible. Recent historical liveries also gained the nicknames candy car, and jam (US jelly) sandwich for similar reasons. All were unofficial nomenclature. Panda cars were so named because of their livery, too, though they were blue-and-white and not black-and-white, and the term was an officially adopted one. As an aside, "jam jar" is rhyming slang for any car or automobile.
Bent: stolen/criminal/corrupt.
Bird (lime): time, a prison sentence. ("Robbo's doing bird in Leicester prison").
Black Mariah: an obsolete term for a black police van for the conveyance of prisoners, also called a "paddy wagon", especially in Liverpool, where both police and criminals might possibly be of Irish origin or descent. Replaced more recently by white vehicles often run by private companies.
Blag: a heist or robbery.
Bloke: a man.
Blower: a phone/telephone, as in "get on the blower, you need to talk to the guv'nor".
Blues and twos: police activating their lights and (often two-tone) sirens.
Boat (race): rhyming slang for "face" (specifically one's visage). There was a rather sexist pop song in the 1970s which contained the line "Nice legs, shame about the boat race".
Bottle (and glass): rhyming slang for arse (US ass) using the London elongated vowel in "glass"). To have "lost your bottle" is to have become afraid, especially after commencing a hazardous activity.
Brass: a prostitute (from "brass rail" = tail). Also see "Tom".
A separate expression, "brass monkeys" is not rhyming slang and has no relation to the above example. "It's brass monkeys outside" means that it's cold. The full expression is "it's cold enough to freeze the balls off a brass monkey" (a variant sometimes heard is "I just saw a brass monkey go passed looking for a welder", but this is to confuse the origin of the saying. A brass monkey was not a metallic simian. It was a triangular metal frame, presumably used until the 19th Century in the British navy, on which cannon balls were balanced prior to immediate use. In extremely cold weather the triangle would contract, and the cannon balls fall from the frame).
Brief: a solicitor (US lawyer). I don't know whether it additionally refers to barristers (not to be confused with baristas).
Century: £100.
Clock: to record, notice, or see, as in "have you clocked the 'geezer' in the corner?".
Collared: caught.
Collar felt: to have one's "collar felt" is to be arrested. Imagine an officer grabbing a villain by the back of his neck.
College: Prison.
Crack of sparrows: combines two expressions for an extremely early time of day—1) "the crack of dawn", and 2) "Sparrow's fart".
Detained at her majesty's pleasure: to be imprisoned. Like "sent down", it derives from a legal/courtroom expression.
Diamond geezer: someone who can be relied upon. See "geezer", below.
Do a runner: to run away/"leg it"/"scarper". "He's done a runner, Guv".
Dog (and bone): a phone/telephone, as in "get the guv'nor on the dog, I need to talk to him".
Done up like a kipper: to be made a fool of, exploited, "framed", or to be manipulated to act in a way contrary to one's best interests.
Drag: a "blag" or theft.
Drinker: a public house or pub.
Drum: a house/home.
Drummer: a burglar.
Face: As well as its literal meaning, "face", it sometimes denotes a known criminal, or just a person. See "bloke" and "geezer".
Factory: a police station.
Firm: a criminal gang.
Form: previous convictions.
(my) gaffe: (my) home, or "drum".
Geezer: a man/"bloke"/"face". Unlike the US usage, "geezer" doesn't necessarily describe an elderly man unless preceded by the word "old".
Give his drum a spin: turn over/search the premises of his home.
Give us a bell: call me on the telephone.
GBH of the ears/earhole: GBH is the common abbreviation of the crime of "grievous bodily harm". GBH of the ears is a "dressing down" or a "telling off", a reprimand, though it often refers to nagging from the "trouble and strife".
Grass: an informer or "nark".
Guest of her majesty: a prisoner.
Guv'(nor): [governor], Informal address of a Detective Inspector or Detective Chief Inspector by those of lesser rank. Higher ranks are always "sir".
Half inch: to "pinch" (steal).
Have it away on your toes: to run away (but to simply" have it away" is to have sex. There's no connection between the two).
Hookey: most probably stolen or of dubious origin.
Knock over: to rob—"Derek's firm knocked over the bank".
Iffy: uncertain (especially of legitimacy).
Leave it out: an exhortation to stop irritating behaviour.
Leg it: run away. See "do a runner", or "scarper". The Brit equivalent of "take it on the lam" or "let's beat it".
Legit: legitimate/ not crooked.
Lift: steal.
Manor: either the locale served by a police station, or one's home turf (US equivalents—the precinct or 'hood).
The Met: the Metropolitan police Service.
Moby (Dick): jail or "nick". See below.
Moody: "dodgy", someone/something of uncertain or dubious provenance (equivalent to US "sketchy", which in Britain tends only to mean "vague").
Mush: slang for a "face", either literally one's visage, or (figuratively) a criminal person, or even just a "bloke" or "geezer". Used in expressions like "I smacked him in the mush" or the warning "watch it, mush".
Nark: an informer or "grass".
Nick: steal (but also to arrest).
The nick: specifically the jail/gaol in police stations, but also a police station or a prison.
Nicked: to be arrested.
Nonce: a child molester.
On your arches: "let's go"/prepare to leave quickly.
Paw patrol: Police dog handlers and their canine colleagues.
Perp: perpetrator.
Peter (Pan): a can, either a safe to be cracked or a prison cell.
Pinched: arrested (but also stolen).
Ponce: a pimp, but may also refer to an expensively or ostentatiously dressed man.
Porridge: a prison sentence. Derived from the alleged diet fed to 19th Century prisoners.
Pull: arrest or detain (but also to have gained the attention of a member of the opposite sex, as in "not now, mate, I think I've pulled").
Put an ear on their phone: bug the telephone.
Scarper: from the rhyming slang "Scapa Flow", to go (quickly)/"do a runner"/"leg it".
Schtum: widely adopted Jewish word for silence, as in "keep schtum"/say nothing.
Sent down: to be sent to prison. Like "Detained at her majesty's pleasure", it derives from a legal/courtroom expression.
Scooby (-Doo): a clue, usually used in phrases like "he doesn't have a Scooby what's going on".
Shovel (and pick): the "nick". See above.
Slag: a general term for a contemptible individual. The lowest of the low. Often applied to particularly violent or depraved criminals (but it's also a politically incorrect term for a woman of exceptionally loose morals).
Smudges: photographs.
Skip'(per): Informal address of a Detective Sergeant by those of lesser rank.
Snout: A "grass", "nark", or informer. "Snout" also refers to tobacco or cigarettes in prison.
Spin his gaffe: search his home or business premises.
Stir: a prison sentence. Related to "porridge".
Stitched up: see "done up like a kipper", to be exploited, gulled, or left holding the baby.
A super: a police superintendent*.
Sweeney (Todd): the Flying Squad, a swift-response division of the Metropolitan Police specialising in large-scale and violent robbery.
Tea leaf: a thief.
Tom: has various meanings in slang, in this context mainly (1) a prostitute. It's thought to derive from either an Australian term for an attractive woman "Tom(-tart)"—almost rhyming slang for "sweetheart", "Thom(as More)"—rhyming slang for whore, or "Tommy (Tucker)—rhyming slang for f*cker;
But there is also (2), rhyming slang "Tom (and Dick)"—to feel or be sick ("Uncle" has the same meaning, deriving from "Uncle (Dick)");
And (3) From Tom (tit)—the rhyming slang for sh*t.
Tom (Foolery): rhyming slang for jewellery (US jewelry). "Someone knocked over Tiffany's and nicked a load of Tom".
Tom: (1) a prostitute. (2) An abbreviation of "Tom and Dick", to feel or be sick. "Uncle" has the same meaning, deriving from "Uncle Dick".
Tom (Foolery): rhyming slang for jewellery (US jewelry).
Tooled up: to be armed, or to "come heavy" as they used to say in The Sopranos.
Trumpet: telephone, as in "get on the trumpet to the Sweeney".
W: an extreme abbreviation for a search warrant.