The business on...Stuart Gulliver, HSBC Chairman, Europe / Middle East

The man who would be king?

Maybe one day. HSBC boss Michael Geoghegan isn't going anywhere for a while, but Mr Gulliver, head of investment banking globally, and the whole bank in Europe and Middle East, is now widely seen as his most likely successor.

A big player in the City, then?

For now at least. But Mr Gulliver is dropping broad hints that he and his bank might quit the City if banking reform does not go their way.

Britain's biggest bank leaving? Isn't that unthinkable?

Not at all. HSBC, like rivals including Barclays and Standard Chartered, is concerned about the ongoing Commission on Banking, which the Coalition Government asked to look into the sector following the financial crisis. If the Commission says the largest banks should be broken up, Mr Gulliver warns there will be "significant implications for where we may choose to headquarter our institution".

Where would they go?

The clue is probably in the name – HSBC does, after all, stand for Hong Kong and Shanghai Banking Corporation. Mr Gulliver insists the bank's preference is to remain in the UK, but HSBC has already relocated its chief executive's office to Hong Kong, emphasising the importance it attaches to its Asian businesses.

This sounds like a threat.

Well, Mr Gulliver, a 30-year veteran of HSBC, is a tough cookie and no stranger to international travel. He worked for the bank all over the world before moving to London in 2002 to run its investment banking division. He shared that role for a period with John Studzinski, a banker with a much more high- profile reputation, but outlasted him.

So will HSBC really leave?

If it is really asked to choose between giving up its investment banking business and remaining as a British-based company, then probably so – certainly if Mr Gulliver has anything to do with the decision. You can see his point: the investment banker knows that his business contributes more than half of HSBC's profits.