Stuart Glendinning, managing director at moneysupermarket.com, said: "The reality is that Provident is servicing a part of the market no other bank will touch.
"Arguably, the bigger problem is there are millions of adults who cannot obtain unsecured credit. Non-homeowners, especially with some history of late or missed payments, are the modern-day lepers as far as the banks are concerned.
"Provident will only lend small sums, typically £500, but everything is clear and straightforward. They do not credit score or apply early repayment penalties and the rate you see is the rate you get.
"It would be stretching things to claim they offer a social service, but for many it is Provident or a loan shark - and I'd prefer the former any day."