The former headteacher of St Aloysius College has been cleared of wrongdoing nine months after he was arrested as part of a £70,000 fraud investigation at the school.

In an exclusive interview, Tom Mannion told us he felt “extreme disappointment tinged with anger” about the whole affair, which ended his 50-year teaching career.

He was arrested during a senior leadership team (SLT) meeting at the Archway school on January 17 and thrown in a cell for four hours at Tolpuddle Street police station.

It concerned fraud surrounding the purchasing of MacBook computers through the school’s accounts.

The investigation is ongoing, but after nine months of silence from police, Tom has been told no further action will be taken against him.

He said: “I just feel it’s important that my side of the story is out there in the open so the many people I’ve worked with over the years can see I never would even dream of doing anything that would affect youngsters’ education or funding.”

Recalling the arrest, he added: “We’d been having an SLT meeting and the police arrived. The secretary came rushing in saying: ‘“The CID are here.’ They came in and said: ‘We are here to inform you that you are under arrest.’

“I said: ‘What? Are you joking? What’s this about?’ and they said: ‘Potential fraud.’

“I then was taken to the police station and put in the cell. It was horrible.”

Tom, who in 2015 was made an OBE for services to education, spent four hours locked up while police searched his home for computers. They found nothing.

He was given a duty solicitor, who he says told him to answer “no comment” to all questions because she believed police were holding information back.

After his release Tom heard nothing from the force until a letter three weeks ago saying no further action was being taken.

He says “has a good idea” who made the initial report implicating him, but isn’t certain,

The day after his arrest, he returned to the school and told staff what had happened.

“The last thing in the world I wanted was rumours flying around,” he said. “I was very, very keen I was left in school working doing my job while the investigations took place, because I knew I had no part to play in any of this.”

The Diocese of Westminster had other ideas, and he was suspended while the investigation took place. With no sign of any updates, Tom’s retirement was brought forward from August to May. He got no card or well-wishes from anyone there.

“I felt that was shocking,” he said. “I’d worked in Catholic education for over 50 years and I was retiring in August. Am I going to be stealing a few computers, given I’ve fought tooth and nail for 50-odd years to make sure every penny went to the needs of children in schools?”

He believes the diocese was “happy” he was going because he opposed the potential academisation of the school. He is now writing a strongly-worded letter to them and the head of education at Islington Council about his treatment.

Despite never worrying about further action by the police, the situation did take its toll. Tom developed a nerve problem that affects his joints and is “absolute murder”. He puts it down to the investigation hanging over his head.

Tom, who began teaching in 1965 and has worked at schools in Camden, Tower Hamlets and Hackney before St Aloysius, said he has been doing “a lot of travelling” but has been at a loose end for much of the year.

“If a wall needs painting, I paint it,” he quipped. “If it doesn’t need painting, I paint it.”

One positive has been the reaction from his former students, which he says has been excellent.

“I bump into them – they’re great,” he said. “They are absolutely terrific. It’s a bit embarrassing at first but word has got around I had nothing to do with it.”

We have been unable to contact the diocese for comment.