The financial watchdog has been told to apologise to a north Norfolk whistleblower for revealing his identity to the bank he was complaining about.

Mark Wright, a former manager at the Royal Bank of Scotland (RBS), made allegations to watchdog the Financial Conduct Authority (FCA) that files had been falsified at the bank.

During enquiries in 2013, the FCA disclosed his name to RBS.

The FCA sought to justify revealing his name by saying that Mr Wright had already taken his allegations to RBS and to “a range of public figures”.

Mr Wright’s allegations were “groundless”, the FCA said, but during its investigation it admitted revealing his identity to the bank.

The Financial Regulators Complaints Commissioner, which handles complaints against watchdogs, has now ordered the FCA to apologise to Mr Wright.

The Commissioner dismissed the FCA’s justification for revealing the whistleblower’s name.

In a decision published this week, the Commissioner wrote: “I have found some of the FCA’s arguments unconvincing: they have sought to justify the disclosure through inferring reasons when there is no contemporaneous record to confirm it.”

The FCA told the Commissioner: “We of course recognise, with hindsight and given the history of this matter, that it would have been preferable to obtain explicit confirmation from (the complainant’s representative) that (his) name should be shared... by the FCA”.

But it took months to get to that point.

The FCA had “repeatedly” argued that it was “necessary” for them to contact RBS to answer Mr Wright’s allegations.

Asking the FCA to apologise to Mr Wright, the Commissioner said: “The FCA should have been cautious about disclosing the complainant’s name, whether or not he was classified as a whistleblower.”

Mr Wright spoke out about his experiences as a whistleblower at RBS in this newspaper last year.The 44-year old worked for NatWest and then RBS in Norfolk from 1988 until 2012 and worked his way up to the wealth management section of RBS.

He had an unblemished record until 2005 when he began raising concerns that customers’ files had allegedly been falsified in the section of the bank which is meant to make sure the rest of the bank is behaving – compliance. RBS denies any wrongdoing and the allegations were dismissed by the FCA.

He finally left the bank in 2012 after his GP had diagnosed him with long-term mental health problems.

His case has been taken on by his MP, Norman Lamb, who is expected to raise the issue in the House of Commons on Thursday during a debate on RBS put forward by Norwich South MP Clive Lewis.

RBS denies wrongdoing.