City watchdogs are set to probe Barclays' chief executive Jes Staley after he attempted to identify a whistleblower at the bank.
Barclays said it will issue a formal reprimand and will make a "very significant" adjustment to Staley's bonus.
The Financial Conduct Authority (FCA) and the Prudential Regulation Authority (PRA) will probe Barclays' boss after he attempted to identify the author of a letter raising concerns about a senior employee in 2016.
"I have apologised to the Barclays board, and accepted its conclusion that my personal actions in this matter were errors on my part. I will also accept whatever sanction it deems appropriate," Staley said.
"Our whistleblowing process is one of the most important means by which we protect our culture and values at Barclays and I certainly want to ensure that all colleagues, and others who may utilise it, understand the criticality which I attach to it," he added.
The board concluded Staley "honestly, but mistakenly" believed that he was permitted to identify the author of the letter.
Barclays' board said Staley "made an error in becoming involved with, and not applying appropriate governance around, the matter, and in taking action to attempt to identify the author of the letter".
Shares in the lender dipped 0.72 per cent at 213.75p at the market open.
Barclays said it will continue to review the position of other employees involved in this matter.
John McFarlane, chairman, said: "I am personally very disappointed and apologetic that this situation has occurred, particularly as we strive to operate to the highest possible ethical standards.
"The board takes Barclays culture and the integrity of its controls extremely seriously.
"Taking into account both the circumstances of this matter and his otherwise exemplary record since joining Barclays, including contributing significantly to improvements in Barclays culture and controls, Jes continues to have the board’s unanimous confidence and it will support his re-appointment at Barclays annual general meeting on 10 May 2017."