Loyalty goes a long way, and for the banks that supported BP with credit facilities during the catastrophe of the past few months it is pay-back time.

As the beleaguered oil group sets in motion plans to divest $30bn (€22bn) of upstream oil and gas assets over the next 18 months, it appears that the banks which provided BP with access to their balance sheets will be first in line to pick up the mandates as M&A advisers.