As the Telegraph reports:

Lord Ashcroft, the major Conservative donor, will be forced to reveal whether he pays tax or stop funding the party, under new election rules. The move is seen as a direct attack on the peer, a Tory deputy party chairman who has bankrolled Conservative candidates in marginal constituencies to the outrage of opposition politicians.

On being made a Conservative peer in 2000, Lord Ashcroft gave an assurance that he would pay UK taxes, but has since refused to discuss his affairs saying that they are private. … The amendment, which was nodded through without a vote on Monday night, would effectively ban anyone who did not pay taxes donating more than £7,500 in a single year.

It was an interesting debate if the Hansard transcript is any guide. You can read Lib Dem shadow justice secretary David Howarth’s contribution HERE, excerpt below:

The principle behind the amendments and the original proposal in the House of Lords is simply that those who seek to distance themselves financially from this country by using their tax status to reduce their tax liability have, by that very act, distanced themselves from monetary participation in politics. That is different from participation as a voter. It seems absolutely crucial to make that distinction, especially as the Government have now introduced proposals—about which I am fairly relaxed—that mean that the rule applies only when the sum of £7,500 is involved. That is a very large donation, in my view. … I am not denying that people who go abroad have the right to vote, but I am saying that those who go abroad and then seek to change their tax status to reduce their liability distance themselves from monetary aspects of the political system of this country in a way that should lead to a restriction on their right to influence others through money. …

Throughout the debates on the Bill, for almost a year, the Government have said that it is not possible to make any further progress with the Hayden Phillips proposals, with the cap on donations that would apply to everyone, with global spending restrictions and with a fair resolution of the relationship between the Labour party and the unions, because there was no consensus. In effect, the Conservative party had a veto on any progress on those matters. We now reach this late stage on the Bill and … the Government have broken that consensus. … I am glad that the consensus on this matter has been broken. I simply regret that it was not broken earlier.

David gave a slightly pithier quote to the Telegraph, though:

“Jack Straw has finally bowed to pressure from across Parliament. Now Tory donors will have to pay their dues to the country before they pay their subs to the Conservatives.”