Ex-Transport Secretary Stephen Byers has "apologised unreservedly" in the Commons for a factually inaccurate statement to MPs about Railtrack.
Mr Byers says he did not lie or deliberately mislead MPs
He was cleared by the Commons standards committee on Tuesday of lying to the transport committee in 2001, but told to apologise for telling an "untruth".
He said he was grateful the probe had concluded he did not lie about how Railtrack was wound up in 2001.
But he acknowledged its call for an apology for giving inaccurate evidence.
The North Tyneside MP has already made a personal statement to the Commons, but the committee said he had been wrong to try to justify his mistake and should now "apologise unreservedly" to Parliament.
On Wednesday, Mr Byers said: "The committee recognised that, whilst in my personal statement of the 17th October I had accepted that I gave a factually inaccurate answer, they concluded that I should have apologised unreservedly for having done so.
"I accept the committee's conclusion and I therefore offer my unreserved apologies to the House."
The controversy arose following a court case brought by Railtrack shareholders over the company's collapse in October 2001.
The "lying" complaint centred around the Commons transport committee grilling of Mr Byers in November 2001.
Conservative MP Chris Grayling asked Mr Byers if he had begun discussing a change in status for Railtrack before a key meeting in July 2001, at which the company's chairman warned Mr Byers of the financial difficulties.
Mr Byers told MPs that he had not.
But last year he admitted in the course of the High Court case that his answer had been untruthful.
His admission came after the court heard he had ordered an options paper on Railtrack, set up a joint working party with the Treasury to discuss Railtrack's future, and had discussed options with the prime minister before the July meeting.
In their report on Tuesday, MPs on the Commons standards and privileges committee said Mr Byers was not guilty of "contempt" of Parliament, despite being untruthful.
"We do not believe, on the evidence we have seen, that Mr Byers lied to the transport sub-committee as alleged," says the committee.
The MPs say the government had not embarked on a clear strategy of restructuring Railtrack, despite officials working on possible options.
And they say Mr Byers had "no obvious motive" for deliberately misleading the committee.
The committee brushed aside Mr Byers' claim that his answer was influenced by the "political context" of the Tories claiming there was a government plan to push Railtrack into administration.
It points to the ministerial code which says giving truthful information to Parliament is of "paramount importance".
"There can be no circumstances where it can be justified to derogate from this obligation for political reasons," says the report.
"Mr Byers' answer to Mr Grayling was factually inaccurate, and the political context cannot be used to justify this."
And the MPs suggest the ex-Cabinet minister almost misled Parliament again when he apologised for his original error.
"Mr Byers was unwise to try and devise retrospectively an explanation for his inaccurate answer," says the report.
"We also believe that, in his personal statement, he came close to repeating the error for which he had apologised."