Deloitte & Touche, advisers to the Royal Bank of Scotland in its takeover bid for NatWest, is a little red-faced at the moment. RBS had claimed in its proposals, audited by Deloittes, that one of the benefits of a merger would be improved performance through the integration of the two bank’s computer systems. Unfortunately, NatWest managed to lay their ever-so-grateful hands on a Deloitte report claiming US bank mergers had hurt shareholders’ interests because, guess what? … combining computer systems is more difficult than everybody thinks. Ooops.