The jailing of ex-MP Denis MacShane for making bogus expense claims was "not justice", said his former Labour colleague Tom Harris.
The former transport minister tweeted that it was an "awful day":
Utterly sickened by jailing of @denismacshane. This is not justice.
Thoughts are with my friend and former colleague @denismacshane on this awful day. A good man.
Harris also made a reference to Liberal Democrat David Laws, who has been appointed a minister despite revelations that he claimed allowances to pay his partner rent for the London flat where they lived.
If only @denismacshane had claimed he was only only trying to cover up his sexuality, he'd be back on the front bench by now.
The Taxpayers' Alliance have said "justice has been done" after Denis McShane was sentenced to six months in prison after claiming more than £13,000 in fraudulent expense claims.
The political director of the organisation, Jonathan Isaby, said the former Labour minister "routinely forged receipts to take taxpayers' money" and that it was not up to the taxpayer to fund Mr MacShane's trips around Europe.
The deception shown by Denis McShane was "calculated and designed" a judge has said during the sentencing of the former Labour minister.
Mr Justice Sweeney told MacShane, who was sentenced to six months in prison, his dishonesty had been "considerable and repeated many times over a long period".
The ex-MP pleaded guilty to false accounting by filing 19 fake receipts for "research and translation" services, and subsequently used the money to fund a series of trips to Europe.
"You have no one to blame but yourself," the judge said.
The judge said MacShane had shown "a flagrant breach of trust" in "our priceless democratic system".
Mr Justice Sweeney has sentenced former MP Denis McShane to six months in jail saying that he had been deliberately dishonest on many occasions and over a prolonged period.
He accepted that the 65-year-old had not personally profited from the faked expenses claims, which totalled £12,900, but said that his action had risked damaging "our priceless democratic system".
He pleaded guilty last month to 19 counts of false accounting.
As the sentence was delivered, McShane muttered "cheers" in an ironic manner and has he was led past the press bench on the way down to the cells he said "quel surprise", suggesting that this was a punishment he had anticipated.
Disgraced former Labour minister Denis MacShane has been jailed for six months at the Old Bailey after admitting making bogus expense claims amounting to nearly £13,000.