Why has the popular head of a Catholic school in west London been suspended?

Cardinal Wiseman School in Ealing, west London, is proud of its headteacher. Its website trumpets a "track record of outstanding achievement" beginning in September 1997 when "a new headteacher, Mr Patrick, arrives." The school's GCSE results in 1998 and 1999 were the best it had known. In 1999 it was named the second most improved school in London by the Times Educational Supplement and one of the country's best technology schools by the Technology Colleges Trust. The next year Ofsted called it "outstanding". And so on, pages of it, right up to another "outstanding" from Ofsted in 2008 and one from the Roman Catholic Diocese of Westminster this year.

What the website doesn't tell you is that Paul Patrick, 53, hasn't been allowed into the school since March. He is barred from speaking to anyone associated with it, and no one wants to talk about him. Local MP Steve Pound used to visit the school regularly and bathe in Mr Patrick's reflected glory. Now a written statement from his wife, the school's chair of governors, Maggie Pound, told me: "Steve Pound has no formal connection with the school, he is no longer a parent of a pupil, nor is he a governor and the school is not in his constituency." The school is just the other side of the constituency border.

At the Diocese of Westminster, a press officer told me that the diocese would not answer any questions. He refused even to give me the name of the Diocese official who dealt with the case. That official is Mike Pittendreigh, assistant director of education. In March, Mr Patrick arrived home from Cuba – one of his unconventional, but apparently successful, innovations is a link with a secondary school in Havana – and received a call at home from Mr Pittendreigh asking him to come straight to the diocesan office: there were questions about his expenses.

The governors decided not to allow Mr Patrick to enter the school, to stop him from contacting anyone "associated with" the school, and to call in the police. The police asked the chair of governors whether they wanted a police investigation, or to investigate themselves; Mrs Pound opted for the police.

So Mr Patrick stayed at home for a month waiting for something to happen; on 21 April it did. At 7am, police officers, some of them from the fraud squad, searched his home thoroughly, and took him to the police station. He was eventually given police bail.

The police told him they were looking for anything on Havana Experience, the organisation he created to run the Cuba exchanges, and he has told friends he gave them all he had. No money went through Havana Experience and it never traded. They suggested he had channelled money to a former school employee now living in Poland. He says the money was her severance pay, and was sent by the school bursar. There was a suggestion that he had used the school's "Building Schools for the Future" money on the Cuban exchange, which he insists is untrue. They said he had travelled to Cuba in business class, thereby wasting public money; he says he did so because he was taking boxes of educational materials, and a business-class passenger had a bigger luggage allowance, so it was cheaper that way.

The police interviewed him again in June, and then, in August, released him from bail and said there would be no charges. Although the governors had opted for a police investigation, they now decided to mount their own, saying they were doing an audit of his expenses, and were appointing another Catholic school headteacher to investigate Mr Patrick's leadership and management of the school.

However, the main charges still related to the Cuban exchange. Two-thirds of the staff, including office staff, have been to Cuba, and pupils go there regularly. Now the link is suspended – the pupils who should have gone to Cuba in February will not be going.

Mr Patrick ran the link – and the school – with a freedom that most head-teachers would envy. His friends say this was all according to a covenant he agreed with the governors when he was first appointed, giving him an exceptional level of autonomy. One long-standing governor, Professor David Foskett of Thames Valley University, was on the panel that appointed Mr Patrick. "We gave him carte blanche to turn the school round," he says. "We needed to give him enough freedom to manage it. We gave him that in writing."

The covenant, say Mr Patrick's friends, was in both his personal file and the governors' file, if he had been allowed into his office when he returned from Cuba, he could have produced it. They say it has mysteriously gone missing. But Mrs Pound says: "No written covenant between Mr Patrick and the governing body has been found to exist."

Mr Patrick has now been suspended on full pay for nearly eight months, and there is no sign of a resolution. His friends insist there is a vendetta, though they are divided about whose it is. Wilder theories include a plot by Cuban exiles to discredit a man who is providing aid for education in Castro's Cuba. Others point out that the Archbishop of Westminster, Vincent Nicholls, is said to be keen to bring Catholic schools under greater central control, and strong headteachers like Mr Patrick get in the way. They say that changes to the school admission criteria, opposed by Mr Patrick, have now been implemented, which give greater priority to Catholics; a non-Catholic sibling no longer has priority.

Whatever is going on, the cost to the public purse is mounting, and a headteacher whom many people, on all sides, call inspirational, is doing no useful work. Mrs Pound claims the governors could not investigate until the police investigation was over: "I am unable to determine how long any investigation which might be required will take, but can give an assurance that matters will be attended to as promptly as possible."

But Professor Foskett thinks it has gone on far too long already. When the police investigation ended, he sent an email to all governors demanding Mr Patrick's reinstatement. The Diocese education officer, Paul Barber, wrote to him accusing him of breaching governors' confidentiality. Professor Foskett resigned from the governing body in disgust. "Paul Patrick is a dynamic leader. They need him back in the school," he says.