Royal Bank of Scotland said it was close to bolstering its board with three new directors as it moved to placate investors on Friday after announcing the third-biggest loss in UK banking history.

The appointments are being seen as the first step to the possible replacement of Sir Fred Goodwin, chief executive, and Sir Tom McKillop, chairman. Both executives apologised for the bank’s losses of £691m in the first six months of the year – a sharp deterioration from the £5.11bn pre-tax profit it made in the same period last year.