Reports said Diamond had been set to receive about £9.5 million.

Diamond's bonus is for his work as head of Barclays' investment arm, Barclays Capital. The US citizen became chief executive of the bank only in January.

Diamond's basic salary for last year was £250,000, while he was also handed an incentive award, contingent on future performance, of £2.25 million.

Amid public anger over bankers' high pay and a fragile economic recovery in Britain, the coalition government last month struck a deal with all of the country's major lenders on bonus pay and overall lending.

Finance minister George Osborne said total bonuses paid to British-based staff of the biggest banks would be lower than last year as part of Project Merlin, brokered after weeks of talks with the Conservative-led coalition.

Responding to Diamond's earnings, Prime Minister David Cameron's spokesman said the government would not comment on the pay of individuals.

The head of Britain's biggest union strongly criticised the award however, claiming there was "no possible justification" for the "enormous windfall."

Unite General Secretary Len McCluskey said the bonus "demonstrates the failure of Project Merlin to bring restraint to the culture of greed within the top of our banks."

The remuneration report comes after Barclays last month said its 2010 net profit rose a third to over £3.5 billion and that it was paying a total of £3.4 billion in staff bonuses.

Diamond, who replaced John Varley as chief executive, is infamous in Britain for pocketing huge bonuses as head of Barclays Capital.

As boss of the investment division, Diamond was at the forefront of Barclays' transformation from a well-run retail bank into an investment banking giant able to compete with Wall Street titans.

As chief executive, Diamond will receive an annual salary of £1.35 million and a potential annual bonus of up to £3.375 million.

He is also entitled to long-term performance-based incentive shares worth £6.75 million.