The billionaire Lord reportedly struck the deal in a private negotiation with Government officials.
By being classed as a non-dom, Lord Ashcroft does not have to pay UK tax on overseas earnings.
In a letter disclosed on his website dating back to March 2000, Lord Aschroft wrote to then party leader William Hague, giving his “clear and unequivocal assurance” that he would become take up “permanent resident” status by the end of that calendar year.
However Lord Ashcroft says: “In subsequent dialogue with the Government, it was officially confirmed that the interpretation in the first undertaking of the words ’permanent residence’ was to be
that of ’a long term resident’ of the UK.
“I agreed to this and finally took up my seat in the House of Lords in October 2000.”
Lord Ashcroft’s revelation came ahead of the information being disclosed under the Freedom of Information Act.
Lord Ashcroft has reportedly donated over £4m to the party.
On his website Lord Ashcroft says: “If home is where the heart is then Belize is my home.”