Parents of children at a grammar school are unhappy at being kept in the dark after the head teacher was mysteriously suspended.

Roger Lock, head teacher at Marling Grammar School, Stroud since 2002, was suspended from Thursday and an investigation into the undisclosed reason for the suspension is under way.

Parents learned of the unavailability of Mr Lock in a letter dated November 5 from chairman of governors Neil Carmichael who is the Conservative prospective parliamentary candidate for Stroud and has a son at the school.

He wrote: "I am writing to inform you that Mr Lock is not going to be available at Marling School until further notice.

"Should you have any particular issues you need to discuss, they should be directed through the acting head teacher, Alyson Mills. Please be reassured that the school is running as normal."

A Gloucestershire County Council spokesman, said: "We can confirm the governing body of Marling School has suspended the head teacher.

"The suspension is without prejudice while investigations are carried out.

"Parents have been informed and arrangements have been made to ensure the school operates as normal with an acting head."

The council also confirmed the suspension related to an employment matter and it had nothing to do with the pupils.

But parents with children at the school are angry they have not been given a reason for the suspension.

One parent, who did not want to be named said: "I was really grateful to Mr Lock because he let my son into the school by the skin of his teeth.

"When I have met him at parent meetings he seemed very competent and authoritative, so it's a bit of a mystery.

"I know the Ofsted report was not very good and I was surprised by that because I thought it would be better.

"But I am very happy with the school and I just hope his sudden departure with no explanation does not disrupt the school.

"I think the parents have a right to and deserve an explanation."

Another said: "My main frustration with the school is communication with parents and when they do communicate, there is no clarity.

"Fundamentally I am happy with the school and what my son is achieving but not with some of the politics which seem to be going on."

Mr Carmichael yesterday refused to comment on Mr Lock's suspension.

Marling's acting head teacher Ms Mills also denied any knowledge of why Mr Lock had been suspended.

"Roger Lock is not available at Marling School until further notice," she said.

"In the meantime I am acting head teacher.

"I know nothing more than you. I was asked to do the position and as deputy head teacher it is absolutely appropriate that I take that position and keep the school moving forward."

Chairman of the parents' society at the school, Andrew Davidson, said he too had not been made aware of why Mr Lock had been suspended.

"I have no idea I'm afraid. I have not been informed of anything officially," he said.

Shortly after Mr Lock became head teacher a fire ripped through the school's design and technology block destroying hundreds of pages of vital GCSE coursework belonging to at least 200 teenagers.

In October 2007 Mr Lock's home in Brimpsfield was badly damaged by fire.