Concern is growing following reports that teachers at Mirfield Free Grammar are “leaving in droves.”

Parents took to social media to express their worry at the number of teachers on the move, said to be as many as 39 out of a teaching staff of 100.

They are believed to include two heads of maths, year heads and teachers of core subjects such as design and technology. It is understood they will leave at the end of the summer term on Tuesday.

The school denied departures were as high as parents claimed. In a statement Lorraine Barker, executive principal, said: “We are a large Academy (1,500-plus students) and our usual turnover of teaching staff is around 15-20 per year. This year it is no different and all positions are filled for September.”

It is understood that 20 teaching staff are leaving for reasons such as retirement, promoted posts, relocating overseas and to support family, described as “the usual end of academic year departures.”

Some parent/staff meetings have taken place with satisfactory results, and principal Hayley Clacy is holding another meeting next week.

Mrs Barker was head at Mirfield before being promoted and sent in as a troubleshooter to sort out failing Colne Valley High School in 2013. She now oversees both sites.

Mirfield parents posting on Facebook group Mirfield Matters expressed their disappointment, frustration and fears. Some accused the school of deliberately failing to inform them of widespread personnel changes.

One wrote: “Gutted to read this. My daughter’s teacher is leaving as it goes but I didn’t have a clue about this.

Another added: “I am also worried there has been a huge turnover of staff over the last couple of years.”

Another posted: “I’ve bought my daughter five leaving cards in the last fortnight, five!”

Another commented: “The school has had a lot of ‘stand-ins’ and children don’t know which teacher is teaching them on a daily basis.”

One woman claimed staff changes had been implemented with “not even a letter home” from the school. Another said: “Still can’t get my head round 39. How did that happen so quietly?”

Someone else claimed 27 of the school’s 100 teachers were leaving.

Mirfield Tory councillor Martyn Bolt said: “For 30% of the staff to be leaving it seems to be more than a clash of personalities. It seems to be institutional.

“Mirfield Free Grammar had a poor reputation. Lorraine Barker addressed that and brought in stricter criteria, which seemed to have a positive effect.

“If the wheels have fallen off we need to understand what has happened.”