Victoria Lambert, 45, of School Lane, Kettering, did not tell the authorities she was living with her partner, dishonestly claiming tens of thousands of pounds in income support over a five-year period. She was jailed for a year at Northampton Crown Court in November after admitting dishonestly failing to notify a change in her circumstances, but had her sentence overturned yesterday at the Court of Appeal.

Three top judges, led by Lord Justice Moore-Bick, reduced her sentence to 22 weeks, meaning she was immediately released from custody.

Lambert first applied for income support benefits in January 1999, when she submitted a claim on the basis that she was a single mother with no income.

But between November 2001 and September 2006, she was living with a partner and failed to notify the authorities of her new situation.

In September 2006, she was interviewed, admitting that she had had a child by the man, but denied that they lived together or were sharing a home.

However, she changed her story when the case went to court and pleaded guilty to receiving £38,473 in overpaid income benefits.

She insisted that there had been an 18-month period when she was living alone and the money had not been frittered away on luxuries.

Cutting the sentence, Lord Justice Moore-Bick, said: "The judge was quite right to note that the offences involved a considerable sum of money and was persisted in over a long period.

"She was entitled to credit for her plea of guilty and for her personal mitigation."