The term cockney refers to working-class inhabitants of London, particularly east London, and the slang used by these people. It is also often used in reference to the "cockney accent", the accent common among London's working-class.
A "true" cockney is often said to be someone born within earshot of the Bow Bells, i.e. the bells of St Mary-le-Bow church in Cheapside in the City of London (which is not itself in the East End). However, the bells were silent from the outbreak of World War II until 1961.

Etymology
The region in which "Cockneys" reside has changed over time, and is no longer the whole of London. As mentioned in the introduction, the traditional definition is that in order to be a Cockney, one must have been born within earshot of the Bow Bells. However, the church of St Mary-le-Bow was destroyed in the Great Fire of London and rebuilt by Sir Christopher Wren. After the bells were destroyed again in 1941 in The Blitz of World War II, and before they were replaced in 1961, there was a period when by this definition no 'Bow-bell' Cockneys could be born. The use of such a literal definition produces other problems, since traffic noise and the current lack of a hospital with a maternity ward in earshot of the church , and it was estimated that the bells would have been heard six miles to the east, five miles to the north, three miles to the south, and four miles to the west.
Thus while all East Enders are Cockneys, not all Cockneys are East Enders. The traditional core neighbourhoods of the East End are Bethnal Green, Whitechapel, Spitalfields, Stepney, Wapping, Limehouse, Poplar, Millwall, Hackney, Shoreditch, Bow and Mile End. The area gradually expanded as more land was built upon.
Migration of Cockneys has also led to migration of the dialect. As Chatham Dockyard expanded during the 18th Century, large numbers of workers were relocated from the dockland areas of London, bringing with them a "Cockney" accent and vocabulary. Within a short period this famously distinguished Chatham from the neighbouring areas, including the City of Rochester, which had the traditional Kentish accent. In Essex, towns that mostly grew up from post-war migration out of London (e.g. Basildon, Harlow and West Horndon) often have a strong Cockney influence on local speech.

Cockney area
Cockney speakers have a distinctive accent and dialect, and frequently use Cockney rhyming slang. The Survey of English Dialects took a recording from a long-time resident of Hackney.[8]
John Camden Hotten, in his Slang Dictionary of 1859 makes reference to "their use of a peculiar slang language" when describing the costermongers of London's East End. In terms of other slang, there are also several borrowings from Yiddish, including kosher (originally Hebrew, via Yiddish, meaning legitimate) and shtumm (/ʃtʊm/ originally German, via Yiddish, meaning quiet Cockney speech

Albert and Harold Steptoe from comedy series Steptoe and Son
The children in the movie Bedknobs and Broomsticks
Colleen the London collie dog on the cartoon Road Rovers
Miss Shirley Brahms Wendy Richard from the comedy series Are You Being Served?
Rudyard Kipling's "The Widow at Windsor"
Jerry Cruncher in Charles Dickens' A Tale of Two Cities
Eliza Doolittle in George Bernard Shaw's Pygmalion (see also My Fair Lady)
The character Toad from Marvel Comics
Gavroche Thenardier in English productions of the musical of Les Miserables (as an equivalent of Paris criminal Argot)
Fevvers in Angela Carter's novel Nights at the Circus
William Somerset Maugham's novel Liza of Lambeth
Me and My Girl (musical)
EastEnders soap opera
Wayne Winston Norris, the chirpy cockney carpenter in Auf Wiedersehen, Pet
Private Joe Walker, infamous cockney spiv fron Dads Army
Guy Ritchie films, such as Snatch and Lock, Stock and Two Smoking Barrels
Eliza Pinchley in Family Guy's spoof of My Fair Lady
Tobias Ragg and the Beggar Woman in Stephen Sondheim's Sweeney Todd
Basher Tarr in the movie Ocean's Eleven
Danny Blue in the BBC TV series Hustle
Wilson in the movie The Limey
In the children's television series TUGS, Ten Cents speaks with a Cockney accent.
In the video game Fable, many of the townsfolk and characters speak with a Cockney accent.
Most characters in the musical and movie-musical Oliver!
The characters in the Thames Television show Minder made liberal use of Cockney slang, and the show brought terms such as porkies into common use
The Hitcher and his accomplices in The Mighty Boosh
Sid, the caretaker in the hit British comedy series Mind Your Language
Rose Tyler, played by Billie Piper, in Doctor Who
Mungojerrie and Rumpleteazer in T. S. Eliot's Old Possum's Book of Practical Cats
Most characters in the movie Green Street Hooligans
Lucy in Jekyll and Hyde the Musical
Most characters in the movie To Sir, with Love
Most characters in Harold Pinter's early plays
Most characters in the plays and fiction of Philip Ridley
Stan Shunpike in Harry Potter and the Prisoner of Azkaban
Yangus in Dragon Quest VIII
The Orks in the Warhammer 40,000 universe (and in the Dawn of War, RTS game series)
The Landlady and her Boarders in Lucky Stiff, a musical comedy
Death of Inhaling Hatmaking Chemicals in Irregular Webcomic!
Corporal Peter Newkirk (played by Richard Dawson) in Hogan's Heroes
Sadie in National Lampoon's Van Wilder: The Rise of Taj
Roman in Armed and Dangerous
Pim Scutney and Rog Gobshire of Team Britain in the movie Beerfest
Almost all characters in Nick Love's films The Football Factory and The Business
Mordor Orcs in Peter Jackson's film trilogy The Lord of the Rings
Sam, Mary, and other minor characters in John Fowles' The French Lieutenant's Woman
Pinky, in "Pinky and the Brain"
Lee-Hom Wang's new song, "Cockney Girl"
Alfred Borden in The Prestige (film) Drama, fiction and poetry

The London Cockneys were a baseball team who played in the International League from London, Ontario but are now defunct.
The Cockney Rejects
Alfie Bass (actor, born in Bethnal Green)
Marc Bolan (singer, musician, born in Hackney)
Bernard Bresslaw (actor, born in Stepney)
Eric Bristow (darts player, born in Hackney)
Max Bygraves (Singer, songwriter and comedian, born in Rotherhithe)
Michael Caine (Hollywood Film Star, born in Rotherhithe)
George Carey (archbishop, born in Bow)
Charlie Chaplin (Hollywood Film Star, born in Walworth)
Chas and Dave
Jack Cohen (founder of Tesco supermarket chain, born in Whitechapel)
Windsor Davies (actor, born in Canning Town)
Roger Delgado, (actor, born in Whitechapel)
Craig Fairbrass (actor, born in Stepney)
Bud Flanagan, (actor, comedian, and singer, born in Whitechapel)
Samantha Fox (model/singer, born in Mile End) Note that she often pronounces her first name as "Samanfer", adding an "r"
Gary Holton (actor, musician, born in Hackney)
Kenny Jones (musician, born in Bow)
Kray twins, Ronald and Reginald (gangsters, born in Hoxton)
Ronnie Lane (musician, born in Bow)
Angela Lansbury (actress, born in Poplar)
Vera Lynn (singer, born in East Ham)
Steve Marriott (singer, musician, born in Bow)
Lenny McLean (bare knuckle/unlicensed boxer/actor, born in Hoxton). Also known as "The Guv'nor". Played 'Barry the Baptist' in Lock Stock and Two Smoking Barrels.
Gary Oldman (actor, director born in New Cross)
Mike Reid (actor/comedian, born in Hackney)
Philip Ridley (artist, writer, film maker, photographer born in Bethnal Green)
Roy Shaw (bare knuckle/unlicensed boxer, born in Stepney)
Terence Stamp (actor, born in Stepney)
Tommy Steele (singer, musician and actor, born in Bermondsey)
Sir Alan Sugar (Businessman, born in Hackney)
Barbara Windsor (actress, born in Shoreditch)
Ray Winstone (actor, born in Hackney See also