Former Essex CC leader Lord Hanningfield has been found guilty of six counts of expenses fraud.
Lord Hanningfield, 70, a former Lords opposition frontbencher, was convicted by a jury of nine women and three men at Chelmsford Crown Court following an eight day trial.
They returned their verdicts after four hours of deliberation.
He had denied fraudulently claiming parliamentary expenses totalling nearly £14,000 between March 2006 and May 2009. The charges relate to six individual one month periods.
I’m devastated but I have no regrets. I did nothing wrong
But the jury found that he unlawfully claimed expenses, including £13,379 for overnight stays in London when he was not in the capital.
He showed no emotion as the verdicts were returned.
Mr Justice Saunders said he would pass sentence in three weeks at Chelmsford Crown Court.
As well as claiming overnight allowances, Lord Hanningfield, from West Hanningfield, near Chelmsford, Essex, also wrongfully claimed £382 in train fares and £147 in mileage by doubling the seven-mile distance from his house to the train station.
Lord Hanningfield, a front-bench spokesman on education until he had the Tory whip withdrawn following the allegations, had told the court 80% of Lords were claiming the maximum allowance.
Referring to the overnight allowance, he said: “You could sleep in a park bench and claim the money.”
He said he felt entitled to claim the allowance as he had needed to return to his home to look after his Burmese mountain dog Jefferson.
As a result he incurred costs, including £20 a day for a dog walking and housekeeping service which he could not claim.
During his evidence he produced a picture of his dog and said it was his closest friend.
He said said he treated it as an allowance for living outside London and “spent a minute a month” completing his expenses form.
As he left court Lord Hanningfield said: “I’m devastated but I have no regrets. I did nothing wrong.”
He added that he may lodge an appeal.
Throughout the trial Lord Hanningfield insisted he had been left out of pocket. He said that he “averaged out” his claims to recoup some of the money he had spent as a result of his parliamentary duties.
He has already paid back some of the claims, including the cost of overnight stays, when he was in fact on a plane to India.
When the former leader of Essex CC was questioned by police he told them to look at the records of other peers and claimed he was not the only one claiming expenses in this way.
He was caught out when detectives examined diaries and a paper trail resulting from the use of a chauffeur driven car.
Detectives spent £18,000 auditing his expenses claims after the allegations came to light.