Plans to clean up Westminster by tightening the rules on MPs' conduct were described as a shambolic mess last night after the Government lost a vote to allow parliamentary proceedings to be admissible as evidence in court.

Plans to clean up Westminster by tightening the rules on MPs' conduct were described as a shambolic mess last night after the Government lost a vote to allow parliamentary proceedings to be admissible as evidence in court.

Justice Secretary Jack Straw ditched a significant feature of the Government's Parliamentary Standards Bill after a surprise defeat in the Commons. Mr Straw said he would "respect" MPs' rejection of the measure as the Bill now continues its progress in the House of Lords.

The controversial clause was defeated after MPs heard warnings that it would have a "chilling effect" on debate. Under the tight three-day timetable for the Bill's passage through the Commons, it was not even debated on the floor of the House.

Several MPs called for the debate to be extended for a sunset clause to be inserted to allow the legislation to be reviewed in a year's time.

It was the second major concession made by ministers to the reform package tabled by Gordon Brown in response to the expenses scandal, after the abandonment of plans to make the MPs' code of conduct legally enforceable.

An SNP amendment, supported by opposition parties, to make it an offence for an MP to intentionally fail to declare financial interests was also defeated.