The region in which "Cockneys" reside has changed over time, and is no longer the whole of London. A common belief 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 1666 by 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 the area around the church is no longer residential and the noise of the area makes it unlikely that many people would be born within earshot of the bells anymore.

A study was carried by the city in 2000 to see how far the Bow Bells could be heard, 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. According to the legend of Dick Whittington the bells could once be heard from as far away as Highgate. The association with Cockney and the East End in the public imagination may be due to many people assuming that Bow Bells are to be found in the district of Bow, rather than the lesser known St Mary-le-Bow church.

The first of the major air raids on London were aimed at the industrial areas and docklands, in the East End of London. For the first few weeks, these raids took place by day and night but the Germans soon switched to night time raids as they were losing too many bombers to fighters during the day (night fighting required airborne radar and direction finding equipment, which only became available as the war progressed). Night time defence of London was mainly ineffective. Although the anti aircraft guns gave a psychological boost to Londoners, they actually brought down few bombers.

After the initial onslaught on the East End, from mid September the Luftwaffe attacked the rest of London and it was in this period that the famous bombing of Buckingham Palace occurred when the then Queen Elizabeth (later the Queen Mother) made her remark about being able to look the East End in the eye.

Air raids took place almost every night and a large number of German bombers dropped hundreds of tons of bombs on the capital. Typically there were 100 to 200 bombers dropping around 200 tons of high explosive and 300 incendiaries although there were raids with 300 and 400 planes with more than double the amount of bombs dropped.