There are about 20,000 accountancy firms in Britain. And 68 of the FTSE 100 companies are audited by just two of them - PricewaterhouseCoopers and KPMG. The gap between the giants and the rest was always wide, but in recent years it has become a gulf. Before its demise, Andersen, smallest of the Big Five, had revenues about three times greater than those of the next firm on the list, Grant Thornton. PricewaterhouseCoopers - the top firm in the City and worldwide - has revenues 26 times the earnings of the tenth-ranking British practice, Baker Tilly.