Thirty-eight Conservative MPs work for firms or companies that advise clients on minimising their tax burden - either by exploiting loopholes or through investment plans such as offshore trusts. The very industry that Mr Clarke is determined not to help.
Tax avoidance within the framework of the law is perfectly legitimate - as most of the MPs involved have been quick to point out. None of the organisations involved concentrates solely on tax advice but they tell clients how to minimise their tax liability. Most have offices in offshore tax havens. There is no suggestion that they do anything illegal or improper.
Archie Hamilton, the former armed forces minister who advises the US investment bank Merrill Lynch, said: 'Basically the name of the game is that people will do all they can to avoid paying tax and will work within the legal limits to do so. The Chancellor is doing all he can to close the loopholes.'
Cheryl Gillan, who lists the accountants Kidsons Impey among her interests, commented: 'Tax avoidance is a complete misnomer when discussing legitimate tax planning. The sort of tax loopholes we talk about are legal tax planning points. I would never advise anyone to break the law.'
Ian Taylor, an adviser to BZW Investment Management, preferred to talk in terms of tax 'mitigation' rather than avoidance. 'Advice on how to organise your own affairs so that you pay no more tax than you need is a very sensible part of financial management.'
Quentin Davies, a consultant to NatWest Securities, and Ms Gillan argued that the Treasury was responsible for creating a series of so-called tax avoidance schemes, by offering tax relief as an inducement to savings plans such as Tessa and Granny Bonds. Malcolm Moss saw mortgage tax relief in a similar light. 'Avoidance is not a dirty word . . . You're not saying there's anything wrong with buying a house, are you?'
Along with a clutch of other MPs, including Tim Renton, the former arts minister, Sir Terence Higgins and Peter Ainsworth, these MPs felt the legitimacy of tax avoidance meant there was no conflict with the Chancellor's words.
Nearly all MPs, including Spencer Batiste, Peter Butler and Peter Temple-Morris, emphasised that they did not advise their companies on tax matters. David Howell, former Secretary of State for Transport, said he counselled the accountants Coopers Lybrand Deloitte on energy and transport issues, while George Walden advised Samuel Montagu and Chase Manhattan, both banks, on international affairs - 'It's small beer, looks terrific in the register of members' interests.'
Sir Edward Heath, who sits on the Public Review Board of the accountancy firm Arthur Andersen, said: 'Arthur Andersen's approach is to ask, 'What are your obligations to pay tax?' They advise on obligations, not how you should avoid them. They have a fundamentally different philosophy from the other firms.'
While many, such as Ian Taylor and Tim Renton, welcomed the Chancellor's attempts to close loopholes, they also warned against coming down too hard on foreign investment. Michael Stern, a consultant to Cohen Arnold & Co, believed 'the Opposition has this idee fixe that everyone, everywhere in the world has a moral responsibility to pay tax to the British Exchequer.'
Ian Bruce, whose own private firm lists the Saudi-American Bank as a client, said: 'I advise Saudi investors coming to Britain. You always have to be aware that loopholes bring in people to invest in the UK, to create jobs.'
Several members, including Gerry Malone, would not comment on their links with the firm or company or what they did for their money. Sir Peter Hordern, a consultant to the accountancy firm Pannell Kerr Forster, said that what he advised them on 'has nothing to do with you, unless you're a customer of Pannell Kerr Forster'.
Patrick Nicholls, who advises Dunn & Baker, a firm of solicitors which said it offered advice on tax and offshore trusts, dismissed enquiries as 'impertinent' before hanging up. Norman Lamont's office, meanwhile, said that to question the former Chancellor's position with N M Rothschild was 'completely ridiculous'.
Sir Anthony Grant, an adviser to Barclays Bank, said: 'Certainly loopholes should be closed . . . but (avoidance) has been going on since the dawn of mankind. The Chancellor blocks up one loophole and along comes some genius and finds another.'