By DANICA KIRKALONDON (AP) â¿¿ A British government minister is being asked to put his money where his mouth is. Opponents of a raft of welfare changes that took effect this week want Work and Pensions Secretary Iain Duncan Smith to make good on a claim that he could live on 53 pounds ($80) a week â¿¿ the amount one welfare recipient said he has left after paying for housing and heat. Asked on national radio Monday whether he could get by on so little, Duncan Smith replied: "If I had to, I would." By late Tuesday, some 300,000 people had signed a petition urging him to prove it. That would mean living on 7.57 pounds ($11.43) a day in London, one of the most expensive cities in the world. It would also reflect a huge comedown â¿¿ a 97 percent cut in his government minister's salary. Duncan Smith defended himself, telling a local newspaper that he'd been unemployed twice and knew what it was like "to live on the breadline." "This is a complete stunt which distracts attention from the welfare reforms, which are much more important and which I have been working hard to get done," he was quoted as saying by the Wanstead & Woodford Guardian. The Conservative-led government's welfare reforms include changes in disability payments, below-inflation increases to benefits and, eventually, the replacement of a patchwork of housing, unemployment and parental benefits with one payment called the Universal Credit. Prime Minister David Cameron has argued that the changes are needed to save money and make welfare more fair, but the tens of thousands of signatures garnered within 24 hours of Duncan Smith's comments underscored the anger over the cuts and worry about their human impact. "You would have to be really tight," 28-year-old Amy Rowland said outside a London grocery store about the 53 pounds a week budget. "You would have to constantly be thinking all the time, constantly watching your step."