Grant Thornton has pulled off a surprise coup to capture RSM Robson Rhodes. Both are UK-based accountancy firms which have extensive tax and private client practices. The new firm will have more than 300 partners and 4,400 staff, operating from 33 locations. The merger, which will take effect on 1 July 2007, creates a frim with annual fees of at least £400 million. It will have one of the biggest clients networks of high net worth individuals among UK accountancy practices. Grant Thornton was the fifth largest accountancy practice until long term rival BDO Stoy Hayward recently inched past it. The new merger will confirm Grant Thornton, as the combination will be called, as number five in the UK – by a wide margin. Although the new Grant Thornton will move closer to the smallest of the Big Four – Ernst & Young – E&Y will still be twice as large. But commentators say that if Grant Thornton gets the new firm right, it will be a magnet for talented practitioners seeking new roles out of the Big Four. It – rather than BDO – will be the principal beneficiary of tranches of post-Sarbanes Oxley work which does not go to the Big Four in the UK. Of all of the firms in the lower half of the top 20, RSM Robson Rhodes was the star. It grew by more than 10 per cent last year. It always saw itself as a high quality national practice although its ambitions to be among the top players have been unrealised. April has recorded a series of key developments in the accountancy sector below the Big Four. BDO has announced its intention to move its five London offices into 55 Baker Street. Chiltern is now exclusively focused on tax after severing its connection with Moores Rowland. Moores Rowland has joined Mazars. This means that the only female senior partner of a UK accountancy practice is at Morley & Scott, which is number 52 in the Top 60. Moores Rowland’s lead partner was Fiona Hotston-Moore.