This is double previous estimates by HM Treasury’s Financial Inclusion Taskforce2, and four times what it was before the financial crisis of 2008, Ffrees said.

Alex Letts, CEO of Ffrees Family Finance, said: “Perhaps retail banks’ current accounts are not really suitable for the majority of the population who want something more modern – and lower cost – but perhaps also it reflects a breakdown in trust between the consumers and the banks after the financial crisis and the well publicised mis-selling scandals. Either way, it reinforces the point that the time is ripe for a new model that works for families on average wages.”

With 440,000 ‘unbanked’ adults, London accounted for 16 per cent of all adults in Britain without a bank account. The capital has more unbanked adults, according to Ffrees, than the city of Liverpool has residents.

The issue is nationwide. Doncaster’s unbanked residents could fill their local football stadium twice over, while Durham, Coventry and Manchester all have figures in the tens of thousands.

Letts said: “We suggest this is the beginning of a consumer drift to alternative ways of accessing their cash. They are saying ‘enough of the old’ and ‘in with the new’.”