LORD Hanningfield has promised to give any damages won from Essex Police to charity.
The peer is suing the force for £6,500 following his arrest over the alleged fraudulent use of his corporate credit card while leader of Essex County Council.
The 72-year-old claims his arrest and detention in September 2011, coming days after he was released nine weeks into a nine-month prison sentence for parliamentary expenses fraud, was unlawful.
During a two-day hearing at the High Court on Thursday and Friday, the former Conservative frontbencher said he had been "traumatised" by the arrest and had nearly suffered a mental breakdown.
"I have given 40 years of my life to public service," said Lord Hanningfield. "The last few years have been so traumatic for me.
"I may seem strong at times but it has been very traumatic."
The peer claims that Essex Police's decision to stage a dawn raid at 6.30am on his West Hanningfield bungalow was unnecessary.
He said when the police arrived at his house he was in bed and was woken by the barks of his Bernese Mountain Dog, Jefferson.
He put on a dressing gown and opened the door. He claims he did not invite the police in but he did not try to stop them.
"I was still in a state of considerable shock and needed to take tablets for blood pressure and depression," said Lord Hanningfield.
"I was told I was being arrested for fraud. I was surprised.
"It was a big surprise to me and I did not understand what was happening."
All charges relating to his council expenses were dropped, which prompted the authority to release details of his £287,000 five-year credit card spending.
Lord Hanningfield called the allegations "ridiculous" and has previously maintained that his council colleagues were fully aware of his spending as leader.
But if he wins damages from the police he said he would donate the money to charity.
Speaking after the hearing, he said: "If they had requested me to go along to be interviewed and talk about these issues I would have done so straightaway.
"I think that they were very heavy-handed about it.
"I don't think people who have been convicted should have different treatment to anyone else."
His solicitor Mark Spragg told the Chronicle: "Lord Hanningfield has not been motivated by money in making this claim because, if successful, he will be awarded nominal damages.
"He was also never trying to prevent the police from carrying out their investigation.
"He was motivated by a desire to show that the police went about this in the wrong way and had no justification for arresting him as they did."
Mr Justice David Eady reserved judgement in the case until later, but a date has not been fixed.
Lord Hanningfield was found guilty at Chelmsford Crown Court in May 2011 of six counts of false accounting in relation to his Parliamentary expenses and ordered to pay back more than £30,000.
