Mirabaud Securities, part of one of Switzerland’s oldest banking groups, has emerged as the unlikely leader in a league table of Aim stockbrokers, illustrating the continued shake-up of London’s broking industry.

According to the latest Hemscott Aim Rankings Guide, published on Monday, the private wealth manager – which only began winning corporate clients on the market five years ago, its chairman said – has displaced Collins Stewart and Numis Securities, both of which have their sights set on bigger brokerships.