Will UK banks leave London as bank levy rises?

London skyline
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Within days of the announcement of a raised charge on banks' debts in the U.K., talk of at least one City of London-based bank relocating elsewhere has emerged.

The prospect of Standard Chartered, the emerging markets-focused bank, moving its headquarters has moved up the agenda again at the bank, with investors urging it to consider a move, a source at the bank with knowledge of the situation told CNBC.

And an economist at the Institute for Fiscal Studies (IFS), one of the most-respected economic think-tanks in the U.K., has warned that the increasing pressure on banks may discourage investment.

"At some point, the environment becomes so unfavourable that everyone shifts wholesale to somewhere else," Stuart Adam, senior research economist at the IFS, told reporters Thursday.

"If I was a bank boss I'd also be remembering that the government introduced a measure that will stop me offsetting losses from the crisis against more than half of profits. I'd be wondering: what's the next restriction that's going to be introduced? And that risk could put me off making investment decisions."

The bank levy, an annual tax on the value of all the debts in U.K. banks, was introduced in 2011 to discourage banks from holding too much debt. It will be raised from 0.156 percent to 0.21 percent following Wednesday's Budget, which the government believes will generate an extra £685 million ($1 billion) for the U.K. coffers in the 2015-16 fiscal year.

Chatter about Standard Chartered moving its base from London to Hong Kong or Singapore is not new. The vast majority of Standard Chartered's earnings come from outside the U.K. – but that has been the case since the two banks which later merged to form Standard Chartered were founded in the Victorian era.

The source at the bank pointed out that it was one of the biggest corporate taxpayers in the U.K. and 9 percent of its pre-tax profits were paid to the bank levy last year.

Still, with new chief executive Bill Winters soon to replace Peter Sands, who is leaving after nearly a decade at the helm, Standard Chartered seems ripe for a shake-up.

A spokesperson from Standard Chartered declined to comment.