Declaring that he had no reason to apologise for the cost of the lavish restorations, the Lord Chancellor said future generations would be "grateful" for the quality of the work done on his grace-and-favour accommodation in the Palace of Westminster.
The Lord Chancellor could not go down to B&Q or Homebase for his wallpaper, he made clear to MPs on the cross-party committee on public administration.
"We are talking about quality materials which are capable of lasting for 60 or 70 years. We are not talking about something down in a DIY store which may collapse after a year or two," he said. "While I understand that pounds 650,000 appears to be a large sum of money I believe it is a noble cause and future generations will be grateful."
MPs were startled at the boldness of a man who, in a few ponderous legal sentences, had transformed himself from a national hate-figure, plundering the public art galleries for his walls, into a self-declared defender of the national heritage.
There was a point during his evidence when the Lord Chancellor appeared to be so impressed by his own replies, that he paused as if expecting applause from the MPs.
Instead, he was relentlessly pursued for two hours by a pack of Tory MPs. He dismissed the row over the refurbishment as a "remarkable storm in a teacup although I entirely accept that pounds 650,000 is a substantial sum of money".
Challenged by Tory MP Andrew Tyrie (Chichester) if he would echo the famous "je ne regrette rien" words of former Conservative Chancellor Norman Lamont.
Lord Irvine replied: "I certainly do not think that any apologies are due.
"On the contrary, I tend to side with those commentators who have said, `three cheers for this being done in Parliament and three cheers for the House committees that decided to do it'."
Living up to his image as one of the most imperious Lord Chancellor's of recent years, Lord Irvine swept aside suggestions that he was looking for a personal spin doctor because he had made such a hash of his own self-publicity since taking office.
The extent of any damage to his authority as Britain's senior law officer will be put to the test today when he unveils a fresh consultation document on proposals for reforming legal aid.
The Lord Chancellor dismissed the row about the cost of his interior decorating as a "storm in a teacup". But it has proved impossible to go ahead with plans for depriving some of the poorest people in the country of legal aid, while at the same time as spending more than half a million pounds on soft furnishings.
He will announce that he is substantially watering down the plans announced four months ago to scrap legal aid for all civil claims. It will be abolished for accident victims, who will be expected to sue with lawyers acting on a no-win, no-fee basis. Legal aid for medical negligence cases will be restricted to lawyers who are specialists in the subject.