Dozens of teachers have called a union hotline to report being bullied and harassed in Glasgow's schools.

The National Association of Schoolmasters Union of Women Teachers (NASUWT) launched the hotline a week ago amid concerns about the treatment of staff.

Around 50 teachers have contacted it to report feeling intimidated, belittled and harassed in the workplace.

Many complained little support was given to them, particularly when they report incidents of pupil indiscipline.

Union members at Rosshall Academy are expected to strike next Tuesday and Wednesday over claims of bullying and intimidation. Staff at All Saints Secondary, meanwhile, are being balloted over industrial action.

Glasgow City Council said the planned strike is "deeply regrettable" and that it has tried to reach a resolution.

Chris Keates, acting general secretary of NASUWT, said: "We opened the hotline in response to concerns raised by members in Glasgow over the abuse of their contractual rights over cover and reports of intimidating and bullying behaviour towards staff.

"The response so far from teachers shows that our concerns were well founded and the hotline has exposed a number of serious issues, in particular the lack of support for teachers in managing pupil behaviour and the lack of respect for them as skilled professionals.

"Teachers should not face threats and intimidation when they are simply trying to stand up for their basic workplace rights and when they are trying to maintain good order and high standards of pupil behaviour. "Given the response to the hotline we will keep it open for a while longer. "

The NASUWT hotline opened on September 27 allowing teachers to report any incidents by text or voicemail.

Calls included one person who said: "When I approached my principal teacher and raised concerns that I was stressed and anxious (I ended up being treated for this long-term including counselling and medication), I was informed that 'your mental health isn't my problem'.

"They then denied ever having made this comment."

A Glasgow City Council spokeswoman said: "It's deeply regrettable that the NASUWT union has not called off the planned strike action at Rosshall Academy next week despite the council's best efforts to try and reach a resolution.

"In fact, the union has declined to either sit around the negotiating table or respond to numerous communications - including an offer to not process deductions for those teachers who have not attended agreed activities which take place out-with the pupil day. "