The chief executive of Barclays has told staff that the UK bank does not need a $90bn (€66bn) merger with its Dutch rival to grow because it has "plenty of momentum" and "opportunities" of its own.

John Varley told staff in a letter filed with the US Securities and Exchange Commission that Barclays is "examining the ABN Amro combination from a position of strength and that means if we choose to walk away, we can".