An influential committee of MPs has asked the UK’s five leading high street banks to report on how they assemble fraud figures, in response to a claim that they understate the numbers by as much as half.

The Treasury select committee was told banks only report fraud if the money lost is irretrievable, neglecting to include large amounts of stolen funds that are recovered.

Andrew Tyrie, chair of the committee, which oversees financial legislation, has asked Barclays, HSBCLloyds, Santander and Royal Bank of Scotland for information about how they assemble the data, saying a change is needed.

“It is important that banks are transparent about these matters and do not, as previously, solely report the sums which are irretrievable,” Mr Tyrie told the heads of the five banks in letters sent out last month that were published on Monday.

He said he was also concerned about banks failing to report “at risk” funds — the total balance of all accounts that criminals have been able to access, whether or not any money was stolen.

Mr Tyrie, who is the Conservative MP for Chichester, has proved a tenacious campaigner on banking reform since taking on leadership of the Treasury committee in 2010.

Richard Clayton, a Cambridge academic and security researcher, told the committee last month that banks understated fraud levels “because they do not want to frighten people”.

He said that banks did publish information where they had had to compensate customers for money that went missing because of card, phone and other banking fraud.

But he added: “Insiders tell me that the going rate is about twice that amount of money goes walkies out of people’s accounts.” Reported figures show that £450.4m was lost to card fraud in 2013 — up 16 per cent from the previous year, but still less than the peak in 2008, according to Financial Fraud Action UK, a trade body.

Cheque fraud was down 22 per cent to £27.5m and phone banking fraud down 8 per cent to £11.6m, but online banking fraud was up 3 per cent to £40.9m.

Mr Clayton told the committee: “The other way of looking at it is that even when your money is stolen, the banks are very good at returning it, and half the time they manage to do so. It is a good news story as well as a bad news story.”

Mr Tyrie said it was “understandable” that banks were reluctant to publish information that could be useful to fraudsters, but “the public and consumer interest in a high level of transparency is also strong”.

The five banks were unavailable for comment on Sunday night.