In the past, HSBC’s periodic threats to shift its headquarters out of the UK may or may not have been a bluff. But it doesn’t look like it is bluffing now.

Following the Chancellor's latest increase in the bank levy, HSBC has come under intense pressure from shareholders to take another hard look at the costs and benefits of relocating. Previously, the calculations have come down in favour of staying in London. This time, there must be a real chance of a different answer.