Barclays boss Jes Staley has moved to quell shareholder unrest over his conduct, insisting he has the full backing of the board as the lender celebrated a doubling of first quarter profits.

Investors have been urged to abstain from a vote backing his re-election at the bank's May 10 AGM after it emerged that Mr Staley was being investigated by regulators for breaking rules designed to protect whistleblowers' anonymity.

However, when asked whether he was offering up his resignation, Mr Staley said: "The answer is no and, as the board said, they unanimously supported me continuing as CEO of the bank."

It emerged earlier this month that Mr Staley will also have his pay docked over the governance failings which saw him attempt to identify a whistleblower at Barclays.

He added: "What I can say right now is limited given that investigation ... as I've said, I made a mistake. I was trying to protect a vulnerable colleague, but I should have left the organisation to handle it. I accept the judgment of the board and we are co-operating fully with the regulatory investigation."

Shareholder advisory group Glass Lewis has raised separate concerns over the number of directorships held by Sir Ian Cheshire, chairman of Barclays' new ring-fenced bank. It prompted Barclays to announce that Sir Ian will cut the number of boardroom roles he currently holds by the end of September.

It is understood that he is planning to drop his role at Whitbread where he serves as a senior independent director.

The bank was keen to instead draw focus to strong first quarter results, which saw profits more than double as its major restructuring programme - which has seen Mr Staley offload unwanted businesses to focus on UK and US operations - draws to a close.

The lender said group pre-tax profit surged to £1.68 billion in the three months to March 31, up from 793 million during the same period last year.

Mr Staley said the bank has nearly completed its overhaul, with only three more businesses to exit in Egypt, Zimbabwe and France.

He said: "We are now just two months away from completing the restructuring of Barclays as a Transatlantic Consumer, Corporate and Investment Bank, and there is further good reason in this quarter's performance to feel optimistic for our prospects."

However, investors were instead focusing on a 4% drop in income from its investment banking markets division to £1.35 billion.

Hargreaves Lansdown equity analyst Nicholas Hyett said that while Barclays has shown signs of progress, "there is disappointment too".

"Chief among them is the poor performance from the investment bank's markets division, which saw income fall 4% compared with 9% growth at Deutsche Bank and a 15% rise among the big five US banks," he said.

It sent Barclays shares down 5% to the bottom of the FTSE 100.

The bank said income for the first quarter rose 16% to £5.8 billion compared to a year earlier, buoyed by a 12% rise in income from its core business, but hit by a one-off impairment charge of £884 million linked its stake in Barclays Africa Group, which it plans to sell down.

Overall, its non-core business dragged on profitability, clocking a £241 million pre-tax loss - though it marked an improvement from the £815 million loss reported for the unit during the first quarter of 2016.