Alan Duncan is one of the richest MPs in the Commons, dividing his time between luxurious homes in Westminster and the countryside.
A £64,000 backbencher's salary is small change for the dapper shadow Commons leader with a weakness for fine clothes and skiing holidays.
So it will come as a surprise to his more cash-strapped constituents to learn he has been caught on camera protesting that MPs were treated "like shit" and that the recent clampdown on expenses had forced them to live on "rations".
It also infuriated senior colleagues as he has been charged with leading on parliamentary reform for the Tory Party as it tries to distance itself from public anger over MPs' lavish claims.
Mr Duncan hurried out a fulsome and unreserved apology today for his comments. Although they were clearly intended as a joke, they could still cost the gaffe-prone shadow Minister his political career.
David Cameron, who was alerted to the controversy on holiday, is unlikely to take a relaxed view of anything that undermines his determination to present a modern face to the electorate.
The outburst was covertly recorded by Haydon Prowse, who previously filmed himself digging a pound-shaped flower bed in Mr Duncan's lawn in protest at his expenses claims for gardening.
After the stunt, which became a big hit on YouTube, the shadow frontbencher invited Mr Prowse to the Commons for a drink to show he bore him no hard feelings.
It is a decision he will have come to regret bitterly. The latest recording by Mr Prowse, who had a camera in his back pocket attached tiny lens hidden in a button, showed him privately defiant about his claims.
Mr Duncan, who has promised to pay back more than £4,000 of gardening expenses, said: "I spend my money on my garden and claim a tiny fraction based on what is proper. And I could claim the whole bloody lot, but I don't."
When he was asked how much he spent on the garden, he replied: "About £2,000 a year and this was £1,000 a year on expenses, you know. It's just, I'm afraid the world has gone mad."
He also articulated a common frustration among MPs that rules on declaring second jobs and curbs on expenses could deter well-qualified people from the job.
Mr Duncan complained: "No-one who has done anything in the outside world, or is capable of doing such a thing, will ever come into this place ever again, the way we are going."
Asked why people would no longer want to become MPs, he said: "Basically, it's being nationalised, you have to live on rations and are treated like shit."
Initially Mr Duncan, who is out of the country, insisted his comments were meant as a joke – and said he wished he had never been so generous as to invite the filmmaker to the Commons.
Hours later he issued an unambiguous apology. He said: "The last thing people want to hear is an MP whingeing about his pay and conditions.
"It is a huge honour to be an MP and my remarks, although meant in jest, were completely uncalled-for. I apologise for them unreservedly."
A Conservative source said: "What Alan said was unacceptable. It is also right he has apology."
But it was not certain last night that he had done enough to save him, with senior figures making little effort to disguise their irritation over the comments.
It comes after tensions ran high between Mr Duncan and Cameron loyalists over his performance in previous post of shadow Business Secretary.
He was switched in January to the become shadow Commons leader – and found himself leading for the party on reforming Westminster in the wake of the expenses scandal.
He was also thrown on the defensive and made himself unpopular with the Tory grassroots after it emerged he claimed more than £4,000 on gardening before agreeing with the Commons Fees Office that his spending "could be considered excessive".
Lord Mandelson, the Business Secretary, pounced on the comments which he claimed proved the Tory secretly opposed Commons reform.
"Alan Duncan is very fond of speaking a good game publicly, but in private talking and acting quite differently. So I'm not surprised he has been found out," Lord Mandelson said.
For his part, Mr Prowse said he felt slightly sorry for triggering the row: "I got on with him really well, he's a very charming, generous guy."
Alan Duncan, 54
Lives: Georgian house in Westminster / Detached house in Rutland.
Job: Shadow Commons leader.
Background: Son of RAF officer and teacher, grew up in Herfordshire.
Childhood: Joined the Tory Party “as soon as my balls dropped”.
Interests: The oil industry, skiing, fly-fishing, political intrigue.
He says: “Basically [the Commons] has been nationalised. You have to live on rations and you are treated like shit.”
Heydon Prowse, 28
Lives: Brick Lane, east London.
Job: Film-maker and editor of alternative magazine Don’t Panic.
Background: Grew up in £1m townhouse in north London.
Childhood: Won a leading role in the film The Secret Garden when 12. Has not acted since.
Interests: MPs’ expenses, anti-terror laws, endangered species.
He says: “We captured the general prevailing attitude in the Commons that he didn’t take the whole expenses scandal particularly seriously.”Reuse content