LAWS designed to stop tax avoidance through investment offshore has changed the way trusts are run, says Peter Stradling, chief executive of Coutts - one of the UK's oldest private banks. In the past, business was booked through the branches or subsidiaries set up offshore, but the administration was done in the back office onshore. However, ''it is increasingly being recognised in the industry that the days of the 'booking centre' operation are numbered,'' he said. More complex and wide-ranging provisions to stop tax avoidance had been introduced. For instance, the doctrine of ''substance over form'' meant that offshore structures must be more than just a presence in name. ''This means actually doing offshore what you are purporting to do there,'' said Mr Stradling. ''For trusts, we need to be able to show that the administration of the trust does actually take place offshore.'' So wealthy people needed to choose a bank with more than a cosmetic presence in offshore centres. ''There is now a need for trust companies with substantial and visible real presence offshore, whose ability to manage corporate structures, and large international trusts in their own offshore premises will be unquestioned,'' he said. However, Mr Stradling thought that computers meant that communications between offshore and parent operations were no longer a problem. ''The availability and price of computer hardware and software has brought modern technology within the reach of even the smaller offshore institutions, both as far as trading and timely accounting are concerned,'' he said. An offshore bank could now supply efficiently and promptly most financial services, making the old style of booking centre anachronistic.