Part-nationalised Royal Bank of Scotland today reported a half-year loss of £794m, compared to a £1.2bn profit last year.

Speaking to BBC Radio 4's Today programme, RBS chief executive Stephen Hester said the bank's restructuring was "going well'', adding: "We are getting risk down, the bad assets - that have been dogging us from past years - are coming down and I feel comfortable with the way that part of the RBS plan is unfolding.''

He said ongoing problems in world banking created "head winds which will affect us in different ways", including writing down RBS’s exposure to Greek debt.

He believed the turmoil on the markets over the last 24 hours, which saw RBS shares plummet yesterday, showed the 2008 financial disaster was "not a banking crisis" but "one of global economic imbalances".

Mr Hester said: "The root of what’s going on and the nervousness hitting markets again is really about how we manage our economies both globally and individually. It is certainly a worrying time."

He demanded "confidence-giving measures" from governments to "address the economic issues rather than specifically banking issues".