The Oxford English Dictionary claims that the first use of the word cockney as a reference to native Londoners was in 1521 and since I did The Knowledge I’ve been telling anyone who cares to listen that I’m a cockney, blithely ignoring the fact that I was brought up in a leafy North London suburb.

For to be a cockney you have to have been born within the sound of Bow Bells, and contrary to the widely held belief the bells in question are not from Bow Church in East London, but St Mary-le-Bow on Cheapside in the City of London. Being born in Fitzrovia, I thought, erroneously, I easily came within its audible catchment area.

A church has existed on the site since Saxon times, and the subsequent Norman church was known as St Marie de Arcubus or Le Bow because of the bow arches of stone in its Norman crypt. The current building was built to the designs of Christopher Wren, 1671–1673, with the 223-foot steeple completed in 1680. It was considered the second most important church in the City of London after St Paul’s Cathedral and was one of the first churches to be rebuilt by Wren for this reason.

On 10 May 1941, a German bomb destroyed the Wren church including its bells made famous in the children’s nursery rhyme Oranges and Lemons.

The restoration was begun in 1956 and the bells only rang again in 1961 to produce a new generation of cockneys, a full 14 years after my birth.

Now according to research at Lancaster University a cockney accent will soon no longer be the hallmark of Londoners. The distinctive accent now known as Estuary Speak is more likely to be found in the Home Counties of Essex and Hertfordshire. The linguists claim that ever-increasing numbers of people in the capital are speaking Jafaican. The hybrid speech, created by successive waves of immigration is a mixture of cockney, combined with Bangladeshi, African and West Indian.

The London dialect could have disappeared within another generation and cockneys in their 40s will be the last generation to speak like stars from the BBC soap. Now the dwindling ranks of cockney speakers are being asked to record their voices for posterity.

Noise consultants 24 Acoustics, produced a sound map of London showing how far the sound of the bells reached in 2012 compared with 1851. Back then, the bells could be heard from the City of London, across Islington, Hackney, Tower Hamlets and into parts of Camden, Southwark, Newham and Waltham Forest. By 2012, on the other hand, the bells could only be heard in a small patch covering just the City and Shoreditch. They concluded that given that there are no maternity units in this area, the likelihood of any “true” cockneys being born is reduced significantly.

24 Acoustics used precision sound level measurements taken while the bells were tolling, taking into account Britain’s prevailing wind, which comes from the southwest. It is this wind that causes the sound from the bells to travel eastwards, they found that the reach of the bells is affected by the ambient noise levels, which was significantly lower 150 years ago.

Without roads or aircraft, ambient noise levels in London would have been similar to those in a rural location — between 20 and 25 “A-weighted decibels” in the evening. A-weighted decibels, or dBA, are an expression of the relative loudness of sounds in the air as perceived by the human ear. This means that the decibel values of sounds at low frequencies are reduced to account for the fact that the human ear is less sensitive at low audio frequencies below 1,000 Hz.

By 2012, ambient noise levels in London vary across the city, but were generally higher than 55dBA, thanks to busy roads, aeroplanes and noise from air conditioning units. Even with the recent lockdown, it’s unlikely that sound levels were at 1851 levels.