Gordon Brown sets off to the Gulf on Saturday with a delegation of business leaders on a mission to drum up billions of dollars of investment for the British and global financial systems.

The prime minister’s four-day trip to some of the world’s richest oil-producing nations comes a day after Barclays unveiled plans to raise up to £7.3bn ($11.7bn) from the region – principally from the state investment funds and royal families of Qatar and Abu Dhabi.