A comprehensive school head has been allowed to keep his job despite being convicted of outraging public decency with another man in a park, the General Teaching Council for England has ruled.

A disciplinary hearing said that in other circumstances Liam Nolan, of Perry Beeches School in Birmingham, could have been struck off for the offence. But he was allowed to return to work because of his record of success in improving the school’s performance.

Mr Nolan, 40, was found guilty of indecency in June, 2007, after being caught in bushes with another man. He was then working at Moreton School in Wolverhampton, but had left school early complaining of a migraine.

On his way home, Mr Nolan claimed he wanted to get some fresh air and decided to walk in a park he knew was a well-known venue for men seeking gay sex.

He said he had walked into bushes at Sandwell Valley to urinate and claimed another man had begun to urinate close to him. Both were arrested by police.

Despite protesting his innocence, Mr Nolan was found guilty at Wolverhampton Crown Court and ordered to pay a Pounds 1,000 fine with Pounds 1,500 costs.

Mr Nolan asked the GTC committee to allow him to carry on his job at Perry Beeches, which he started in April 2007, even though the local council knew the court case was hanging over him.

The committee could have struck him off but said that there were “exceptional mitigating factors”.

“You have previous good history and there has been no recurrence of such behaviour in the subsequent two and a half years,” it said. “More particularly, we have received and heard evidence from independent, external sources testifying to your outstanding skills as a headteacher at Perry Beeches School and to you transforming its standing.

“We also take account of the evidence from colleagues within Birmingham city council and other key stakeholders who speak highly of you and who have persuaded us that the public interest is best served by allowing you to continue to move the school forward in such a remarkable way.”

This year 51 per cent of pupils at Perry Beeches achieved five good GCSEs including English and maths, up from just 21 per cent in 2007. The school was described as inadequate by Ofsted in September, 2007 and was given a notice to improve. A year later, inspectors praised the turnaround at the school and rated it as good.

“The school has made a remarkable journey over the last 18 months and is rapidly improving,” they said.

Mr Nolan told the hearing that he had received dozens of letters of support from parents after his conviction. “People who know me would describe me as a workaholic, and I never take time off through illness. On that day, I woke with a migraine and had to leave school. I needed some fresh air and when I pulled in to Sandwell Valley, the thought of sexual contact was the last thing on my mind. I wanted a breath of fresh air before getting back to my flat.”

He said he felt stupid for having put himself in that situation.

The committee told Mr Nolan that he had displayed a “distinct lack of judgment”. It said: “Teachers, especially those in senior positions, are role models for their students, and offences of this kind, even though a first offence and once committed outside the school environment can adversely affect the reputation of the teaching profession.” It has imposed a reprimand that will remain on Mr Nolan’s file for two years.

Mr Nolan did not want to make any comment after the hearing but his lawyer said he planned to appeal against his criminal conviction.