Lord Ashcroft has saved more than £127m in British tax since he became a member of the House of Lords, according to estimates from Liberal Democrat research.
The annual tax-saving of the Tory party's biggest donor, who took his seat in the Lords in 2000 and so has been involved in setting UK law for a decade, is conservatively estimated to be £12.76m.
Ashcroft, who has given millions of pounds to bankroll Tory campaigning in marginal seats, confirmed yesterday he was non-domiciled for tax purposes after years of speculation.
Liberal Democrat shadow home secretary, Chris Huhne says: "Anyone who wants to pass laws in this country should pay this country's full taxes and not hide behind the special offshore status of non-doms.
"Non-doms have to tell the taxman that their first allegiance is to another country. No-one should be a British lawmaker whose first allegiance is not to Britain."
The Lib Dems are challenging Ashcroft to own up to his total tax-savings.
Huhne says: "If he challenges our estimate of how much tax he has dodged, then there is a simple solution: publish the figure."
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