Mr Duncan originally claimed earlier today that his remarks had been meant as a joke, but he quickly apologised after Tory HQ hit the roof. 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."
Mr Duncan was filmed by green group Don't Panic last month as he showed its members around the Commons. Activist Heydon Prowse had been invited to Parliament as a goodwill gesture by Mr Duncan after the campaigners staged a stunt at the MP's home, digging a pound sign in his lawn in protest at his expenses claims.
Caught out: Alan Duncan complaining
Asked why, he replied: "Basically, it's being nationalised, you have to live on rations and are treated like s**t.
"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."
Asked how much he spent on the garden, he said: "About £2,000 a year and this was £1,000 a year on expenses, you know."
Lord Mandelson was swift to exploit Tory discomfort, claiming that Mr Duncan in his Commons role had opposed government moves to clean up the expenses system. Lord Mandelson told BBC News: "MPs living on rations? Alan Duncan is very fond of speaking a good game publicly but in private talking and acting quite differently." Mr Duncan has already said he would pay back more than £4,000 of expenses, after details of his gardening costs were revealed, including hundreds to overhaul a ride-on lawnmower.
The film also shows an encounter with another Tory MP, Nigel Evans, in the Strangers' Bar. Commenting on some sandwiches, the MP says: "I made these myself. It's my second job!" Referring to the annual MPs' salary, he adds: "Got to have a second income mate, couldn't survive on 64."
Teased that he is "trading down" in an apparent reference to his choice of drinks, Mr Evans also jokes: "This is what it's come to now. Actually I'm paying, that's what it's come to."