The peer and former Essex Council leader Lord Hanningfield has been found guilty of fiddling his expenses.
Paul White, 70, had denied six counts of false accounting relating to his parliamentary expenses.
The prosecution said he had claimed for overnight stays in London between March 2006 and April 2009, when he had actually returned home to Essex.
The peer told the court he had seen it as a “living-out-of-London allowance” rather than overnight subsistence.
The jury at Chelmsford Crown Court found White guilty on all six counts and he will be sentenced in six weeks’ time.
Members of the House of Lords were able to claim up to £174-a-night to stay in London when attending Parliament, if their main home was outside the city.
But the trial heard White had made claims for journeys and overnight stays in London, which he never made.
The prosecution said on occasions between March 2006 and May 2009 when he made claims for overnight stays, he usually made the 50-mile trip home.
But they also pointed out on one occasion he was on a plane bound for India at the time, on others he was “at hotels outside London all paid for by someone else, mainly Essex County Council”.
The peer argued he had subsidised his long years of public service out of his pocket, and said most other peers claimed the maximum under the allowance.
The trial heard he had told police: “It is an allowance scheme, not a reimbursement scheme. Quite honestly, people see it as a way of recouping what we spend.”
White, who was an Essex councillor for 40 years and led the council from 2001 until he was charged in 2010, was made a life peer in 1998. He was a frontbench spokesman on business while the Conservatives were in opposition.
He was suspended from the Parliamentary Conservative party when he was charged. – BBC