A teacher found guilty of sexual offences at a top private school in Edinburgh is still working in classrooms with children at another school in England.

Gordon Cruden, who taught at the exclusive Merchiston Castle, exposed himself in front of teenage boys at the school but escaped any punishment in December after a trial despite being found guilty.

He was given an absolute discharge by the sheriff and continues to work as a French teacher at Bloxham school in North Oxfordshire.

Police Scotland confirmed last year that officers had launched a probe into claims of historical abuse of pupils at Merchiston Castle.

It is the only all-boys independent boarding school in Scotland – serving 7 to 18 year olds - and is based in the Colinton area of Edinburgh.

Fees can reach nearly £29,000 a year, which puts the Merchiston Castle at the high end of the market.

Two former male staff members, both in their 60s, were charged as a result of the police investigation.

The Sunday Herald can reveal that one of the men, Cruden, stood trial at Edinburgh sheriff court and was found guilty in December of three charges of indecent exposure at the school covering a period between 1980 and 1985.

The languages teacher, now 62, had been accused of knowingly wearing a pair of trousers with a large hole in the crotch and sitting with his legs wide open and exposing his genitals. The incidents were witnessed by three teenage boys.

He was not fined or given a jail sentence, but instead received an absolute discharge by Sheriff Kevin Drummond.

This means no penalty was imposed and no conviction is recorded. He is not on the Sex Offenders Register.

A spokesperson for the Judicial Office for Scotland said Cruden lodged an application to appeal but abandoned the move last month.

Despite being found guilty, he is still a French teacher at Bloxham school, which caters for pupils aged 11 to 18.

His biography states: “Gordon Cruden teaches French across all age groups. He is passionate about rugby, coached the colts (U16) team for many years, and holds weekly touch-rugby ‘Cruden’ training sessions throughout the summer term.

“He is also a Warwickshire Society referee. Before most of the school have risen from their beds, he has organised an early morning swimming practice. He was, for many years, Crake Assistant Housemaster and has always tutored in Crake.”

The school flags up its “Christian values” online and promises to nurture a “compassionate spirit so that our students become a force for good in an ever-changing world”.

Cruden was educated at Edinburgh University and did his teacher training at Moray House.

He swam for Scotland in 1970 and it is believed he joined Merchiston Castle in 1977 as a French teacher.

He rose to Head of Modern Languages, trained the swimming team and edited the school yearbook – the Merchistonian - between 1983 and 1985. However, he was listed as one of two “departures” in the 1986 yearbook.

The article on his career at Merchiston noted how, as House Tutor in the Rogerson East part of the school, his “study was frequently the centre of lively social life”.

The piece added: “He was the first Vice-President of the New Common Room and looked after the interests of the resident batchelors in inimitable style.

“To all the many facets of school life in which he involved himself at one time or another, Gordon brought energy, total commitment, drive, efficiency and vigour.

“Thanks to him, many Merchiston boys were able to develop their talents to an extent that otherwise may not have been possible.”

The article did not mention the reason for his exit, unlike another teacher in the “departures” column who was listed as leaving for a promotion south of the border.

Court papers show that Cruden provided an Edinburgh address for a property in the New Town he owns.

He purchased this flat in 2003 and listed Bloxham School as an address during the sale.

No one answered the door of his properties in Edinburgh or Bloxham on Friday.

A minute of a Warwickshire Society of Referees committee meeting from September last year stated that Cruden was “away on business in Edinburgh”.

The Scottish Court Service said: “In respect of this matter after a trial Mr Cruden was found guilty of 3 charges of indecent exposure. The court then without proceeding to a conviction dealt with the matter in terms of section 246 (3) of the Criminal Procedure (Scotland) Act 1995 by way of an absolute discharge.

“The impact of this disposal is that although Mr Cruden was found guilty he has not been convicted of the offences libelled.”

A spokesperson for Merchiston Castle School said: “We have cooperated with the police investigations to the fullest possible extent.”

A Bloxham School spokesperson said: “I can confirm that a member of staff appeared at court in Edinburgh in December. The case was granted an absolute discharge and did not result in a conviction. The safeguarding of our students is our utmost priority and all correct procedures were followed throughout.

“In the light of this verdict, and following legal and Local Authority advice, the member of staff returned to work in January. Oxfordshire Safeguarding and Child Protection has since re-examined the case and confirmed it is appropriate for the individual to resume their role."

The school added that Cruden had declined to comment.

A Crown Office spokesperson said of the second man who had been under investigation by the police: "The Procurator Fiscal has received a report concerning a 69-year-old man in connection with a number of incidents alleged to have occurred in Edinburgh between 1 and 31 March 1977.

“There are currently no proceedings but the Crown reserves the right to raise proceedings should further evidence become available.”