An ageism row is threatening to rip apart a successful Fulham Catholic school.

Furious parents are vowing to oust the board of governors from Holy Cross Primary School in Basuto Road over its plans to sack long-serving headteacher Gerry Mulligan, 68, at the end of this term.

They suspect the board of 11, chaired by Simon Guest since 2005, want to remove the popular Mr Mulligan purely because of his age, but say they are being kept in the dark over his future.

On Monday, a group of parents demonstrated at the Diocese of Westminster-run school and plastered posters and messages of support for the headteacher on the front gates.

The Hammersmith and Fulham branch of the National Union of Teachers (NUT) also stepped into the conflict, warning some staff could quit unless Mr Mulligan's future is resolved.

Police were called to break up the protest, which Mr Guest branded 'unhelpful and unacceptable'.

But Kathleen Fennel, who attended the school in the 1960s and has three grandchildren there, said opponents were defiant.

"Our opinions have been dismissed for over a year and we have had enough," she said.

"This is a democracy – and we are determined to have our views heard. Mr Guest can do what he likes – but until we get answers we will continue to fight the board all the way."

The unrest began in May last year when governors called a meeting but barred Mr Mulligan, head for 22 years, and a teacher board member, from attending.

The meeting's content never came to light – but parents say there has been a whispering campaign against Mr Mulligan and his deputy, Margaret Gillespie, ever since.

One mother who is behind a Facebook support page and petition to save Mr Mulligan, said: "There have been governors approaching parents in the playground asking if they are happy with how the school is being run and giving hints that he is going to be sacked, but there has never been a definitive answer.

"We have been met with a veil of silence and it's appalling. Clearly this is one of the most successful schools in the borough and it's ridiculous what's going on. Mr Mulligan is outstanding - you would never think he was 68 but this can only be about his age.

"His dedication is unbelievable - when it snowed he walked from Streatham two days in a row. He's more like a man of 28.

"If we don't get answers, we'll try and get the board removed."

H&F NUT rep Dennis Charman backed the parents, saying the council has the power to sack governors.

"They can if the board has lost the ability to run a successful school. It happened at Canberra School three years ago.

"We support the authority resolving the problem – and if that means people are removed, so be it."

He added staff had been 'unsettled' by the situation and warned of walk-outs. "Normally when I am called in there are problems between the staff and the head but it's the opposite here.

"It's hard to believe it's his age that's a problem because he does such a good job – it's a mystery.

"Staff may think about leaving."

Mr Guest refused to speak to the Chronicle to clarify Mr Mulligan's future, only issuing a statement through the Diocese which said it is 'working with the local authority to discuss Mr Mulligan's retirement'.

HOLY CROSS GOVERNOR SIMON GUEST'S FULL STATEMENT:

"Holy Cross Primary School is an outstanding education institution.

"The school governors and the current head teacher are working with the local authority and the Diocese of Westminster to plan for Mr Mulligan;s retirement.

"It's important that this is done carefully to ensure Holy Cross will continue to provide the best possible Catholic education for its pupils in the future.

"What has happened outside the school gates and on Facebook was both unhelpful and unacceptable to our school coomunity and our reputation as a Catholic community.

"Photos and personal remarks will not be allowed on school property and should not be put up anywhere in our community."