Shamed former Labour MP David Chaytor was starting an 18-month jail sentence tonight after admitting he fiddled his parliamentary expenses.
Chaytor, 61, forged tenancy documents and invoices to falsely claim more than £22,000 of taxpayers' money for rent and IT work from the Commons authorities.
He is the first ex-MP to be jailed since Tory peer Lord Archer received a four-year sentence for perjury and perverting the course of justice in July 2001.
But Chaytor could be released as soon as the end of May under early release rules for non-violent prisoners who pose a low risk.
Passing sentence at Southwark Crown Court, Mr Justice Saunders told Chaytor that putting him behind bars was one of the first steps in restoring public faith in the parliamentary system.
He said: "These false claims were made in breach of the high degree of trust placed in MPs to only make legitimate claims.
"These offences have wider and more important consequences than is to be found in other breach of trust cases.
"That is the effect they have had and will have on the confidence the public has in politicians.
"They are elected representatives, they hold an important and powerful place in society. They legislate what the public can and cannot do.
"It is necessary their behaviour should be entirely honest if public confidence in the parliamentary system and the rule of law is to be maintained."
Chaytor, of Lumbutts, Todmorden, West Yorkshire, looked gaunt but calm in the reinforced glass dock and made no reaction as he was sent down.
He began his sentence at Wandsworth Prison in south-west London, where he was due to be strip-searched, photographed and fingerprinted before being issued with prison clothing.
The Victorian prison was recently home to WikiLeaks founder Julian Assange, who was temporarily jailed as he fought extradition to Sweden, where he is under investigation for alleged sex offences.
Chaytor faces a potential six-figure legal bill for his defence and part of the prosecution costs, including several hearings at the High Court and Supreme Court.
The former lecturer initially denied the charges but changed his plea after failing to have the case thrown out citing parliamentary privilege and that he could not receive a fair trial because of media scrutiny.
He pleaded guilty last month to three counts of false accounting between November 2005 and January 2008.
The fraud involved bogus documents he submitted to support claims totalling £22,650 for IT services and renting homes in London and his Bury North constituency.
The court heard he only received £18,350 because he had already reached his limit for the IT expenses and was not awarded the full amount for one rental claim.
Prosecutor Peter Wright QC said the properties were owned by Chaytor and his mother, he did not pay out any money and the claims were entirely fraudulent.
The former MP submitted claims totalling £15,275 and was paid £12,925 for renting a flat in Hide Tower, Regency Street, a stone's throw from the Houses of Parliament.
But it turned out that he and his wife had bought the property in 1999, two years after he was elected to Parliament, and paid off the mortgage on it in 2003.
Chaytor also falsely claimed £5,425 between September 2007 and January 2008 for renting a cottage in Castle Street in Summerseat, near Bury, Lancashire.
A police investigation later revealed that this house was owned by his elderly mother, Olive Trickett, who was suffering from dementia and had just moved into a care home.
Chaytor had been granted power of attorney over her affairs and forged a tenancy notice that was apparently witnessed and signed by his daughter.
The final charge related to a £1,950 claim for IT support services provided in May 2006 by freelance computer programmer and Labour volunteer Paul France.
The court heard Mr France, who had earned £100 for previous work, did not ask for any money for his services and the claim was "something of a surprise".
Mr Wright said: "We say Mr Chaytor knew the rules, and we say why else would he produce false documents in support of his claims otherwise?"
In mitigation, James Sturman QC said Chaytor was a "broken man" who had already paid a "quite devastating price" for his errors.
He said the former MP, who has repaid £19,237, displayed "inexplicable stupidity" in submitting the fraudulent documents.
Mr Sturman said: "He accepts he has brought shame on himself, he has brought shame on his family and he has brought shame on Parliament."
Current and former MPs were among supporters of Chaytor who wrote glowing letters of reference to the court.
Under the home detention curfew scheme, the disgraced ex-politician may only have to serve four and a half months of his sentence behind bars before being tagged and released.
Hundreds of MPs were ordered to repay a total of £1.12 million in the wake of the expenses scandal.
Former Barnsley Central Labour MP Eric Illsley is due to go on trial at the same court next week accused of dishonestly claiming £20,000 in council tax and other bills on his second home.
Others facing trial over their expenses are former Scunthorpe Labour MP Elliot Morley and former Labour MP for Livingston Jim Devine as well as Lord Hanningfield and former Tory peer Lord Taylor.
Chaytor may still qualify for a £54,000-plus taxpayer-funded "golden goodbye" payment despite being jailed over his expenses.
Commons Speaker John Bercow directed last year that such payments due to three MPs charged with criminal offences should be suspended pending legal proceedings.
Asked if Chaytor would now be stopped from receiving the cash - designed to ease the blow for MPs losing their seats - a Commons spokeswoman said: "That will be decided in due course."
Any decision over the future of his generous pension was a matter for the trustees of the parliamentary scheme, she said.Reuse content