JPMorgan Chase & Co Chief Executive Jamie Dimon called British Finance Minister Alistair Darling earlier this month to say Britain's 50 percent tax on bankers' bonuses punishes the bank unfairly, a person close to the bank said.

The CEO told Darling the second-largest U.S. bank is a large employer in Britain, it funded British banks during the financial crisis and it did not take any bailout money from the British government, the person said.

Dimon also mentioned the bank's plans to build a European headquarters in London's Canary Wharf to Darling as an example of the bank's investment in Britain, the person said.

According to some news reports, the bank has considered scaling down the plans for the 1.5 billion pound ($2.4 billion) building.

JPMorgan declined to comment.

Britain unveiled the controversial tax on bonuses over 25,000 pounds ($39,750) in early December in an effort to rein in multimillion-pound payouts across the industry. Critics have said the tax could lead to an exodus of bankers and make London uncompetitive.