Elliot Morley has admitted he was Parliament's biggest expenses cheat as he prepared to become the first ex-minister to be jailed over the scandal.
The former environment minister was condemned as "blatantly dishonest" by prosecutors as he was convicted of claiming more than £30,000 on fake mortgage payments.
As his own barrister accepted it was not a question of "if but how long" he faced behind bars, the 58-year-old came under attack from campaigners for failing to own up earlier. The admissions came just days before he was due to go on trial.
Morley, the most high profile of a string of convictions since the expenses revelations rocked Westminster, pocketed £30,428 by claiming for a phantom mortgage and inflating the amount he was previously paying.
The grey-haired ex-Labour MP was solemn in the dock as he entered two guilty pleas for false accounting for his home in Winterton, near Scunthorpe, North Lincolnshire, between 2004 and 2007.
In total, he claimed £16,800 on a phantom mortgage and £15,200 after inflating the amount he was previously paying - for which he should have been entitled to only £1,572.
James Sturman QC, for the defence, told Mr Justice Saunders that his client accepted a jail sentence is likely.
An MP for Scunthorpe since 1987, former teacher Morley was one of Labour's most prominent voices on agricultural issues and the environment.
Jim Devine, the first MP to stand trial in the wake of the expenses scandal, was branded a liar by a judge last month as he was jailed for 16 months for offences totalling £8,385. Two other former Labour members, David Chaytor and Eric Illsley, have already been jailed after pleading guilty to falsely claiming £22,000 and £14,500 respectively. Former Tory peer Lord Taylor of Warwick awaits sentencing after being convicted by a jury in January of falsely claiming more than £11,000 for travel and overnight subsistence.
Morley will appear again at Southwark Crown Court after pre-sentence reports, due to be submitted by May 12.