TONY Williams is the last lawyer left at Andersen's glittering headquarters on the Strand in London. But, unlike the accountants who will shortly embark on new careers at Deloitte & Touche, no desk awaits him. He, like the other 200 lawyers at Garretts, Andersen's pioneering legal arm, were left in the cold by the emergency rescue deal brokered by Andersen with its former rival.