The cost of filtering through information obtained in the proposed global crackdown on tax havens may outweigh the revenue raised, according to a senior tax figure. Frank Haskew, chairman of the ICAEW Tax Faculty, said the core demand will be for all offshore centres to release the names of individuals with accounts in their territories, enabling tax authorities in other countries to track down those who are not disclosing all they should in their home country. 'The exchange of information might be right, but there must be a balance, focusing on risk areas, rather than shed loads of returns,' he said. 'There's so much data they don't know what to do with it. How will HMRC deal with it?' He added: 'We should be more focused and targeted on high-risk people. There's so much information from businesses, it would take them forever to go through it.' But Richard Murphy, of Tax Research UK, denied this was the case. 'They made 25,000 people in the Revenue redundant. How much would it cost to get them back? Tax havens are costing £4bn a year in lost tax. It wouldn't cost that much.' Switzerland and Liechtenstein have both recently agreed to relax banking secrecy rules.