The Government has saved more than £100 million by cracking down on benefit fraud, the Work and Pensions Secretary has told the Commons.
Iain Duncan Smith also confirmed nearly 10,000 people were prosecuted for benefit fraud last year - more than 1,000 up on the previous year.
Mr Duncan Smith was answering a regular questions session in the Commons and was questioned by Conservatives Nadhim Zahawi (Stratford-on-Avon) and Stephen Mosley (City of Chester) about areas where rates of benefit fraud are high.
He told MPs: "The inheritance we got from the last Government was that fraud and error was at £3.1 billion in the benefits system.
"A joint strategy with the HMRC started in October 2010 which was about regional taskforces, which were mobile to look at different areas. They targeted claimants in high fraud areas with visits and phone calls and letters.
"One pilot was completed in Birmingham, two more in Cardiff and Croydon, and evaluation of a fourth is being completed. But so far, since October, just from case cleansing alone we have saved over £100 million.
"We prosecuted almost 10,000 benefit fraudsters in 2010/11, up from 8,200 the year before. In all cases, benefit fraudsters are required to pay back the money that they have stolen."