Liberal Democrat David Laws has resigned as Chief Secretary to the Treasury after admitting he claimed expenses to pay rent to his partner.
He said he could not carry on with the "crucial work" on the Budget while dealing with the implications of the revelations in the Daily Telegraph.
He had earlier apologised and said he would pay back the £40,000 he claimed.
Prime Minister David Cameron and his deputy Nick Clegg paid tribute to Mr Laws saying they hoped he would return.
The Yeovil MP said he wanted to keep his relationship with James Lundie private.
"I cannot now escape the conclusion that what I have done was in some way wrong, even though I did not gain any financial benefit from keeping my relationship secret in this way."No hapless Ethics Commissioner involved, just ministerial accountability and responsibility. Another helpful comparative perspective from the UK.
Now if only the UK press would have zeroed in like a laser beam on how excellent Minister Laws was on twitter. That's big over here. Conflict of interest allegations in the air? Ah, run the story anyway.