Teachers at an independent school are threatening a third strike in a row over pensions after a union criticised a “deeply insulting” approach.

Strikes have already been held outside Abbot’s Hill Independent Girls’ School near Kings Langley during January and December after the school proposed to leave a pension scheme, but staff have said they could walk out again.

Members of the National Education Union (NEU) and NASUWT, The Teachers’ Union fear teachers could lose around 20 per cent of their annual pension payments on average if the school was to leave the Teachers’ Pension Scheme.

The union has said six more days of action could take place after criticising the school for not consulting with members.

Abbot’s Hill did not respond to a request for comment, but have previously said it has met with the unions and the consultation is still ongoing, and no final decisions have been made.

The school has also previously noted almost a quarter of independent schools are planning to leave the scheme, citing an "unrealistic and unsustainable" rise in the level of employer contributions.

However, the unions have said it’s unfair for teachers to take any financial hit and believe the cost-saving measure is unnecessary for the school, with fees starting at more than £4,000 per term.

The NEU has claimed the school has indicated they could use 'fire and rehire' tactics, which would see staff re-employed with new conditions, to leave the scheme if no agreement is reached.

Paul McLaughin, regional secretary at the NEU, said: "We’re encouraging them not to do that, it would be deeply insulting to staff who have continuously done their best to support the pupils in their care. The idea they would just be dismissed and be engaged in inferior terms is not acceptable in any shape or form."

In an open letter last year, teachers said the Teachers’ Pension Scheme provides long-term security for staff and compensates for relatively low salaries.

The NEU said they had received support from parents during the action, but hoped the dispute could be resolved before another walk-out.

Mr McLaughin added: "No parent wants to see a strike at their school, but equally we’ve had an incredible amount of support from parents when they look into or we’re able to explain the issues, they’ve quickly grasped this is no way to treat their loyal staff. 

"We’ve got many, many messages of support from parents, and we’re very encouraged by that but we’re also aware any day of action is causing difficulty for them and we don’t want to take any further action. 

"We really hope the trust will come back and come to use and talk and seek a negotiated resolution."

Abbot’s Hill is the latest independent school to face a dispute over the scheme. It’s believed around a quarter of independent schools are considering or have left the scheme, and teachers at St Francis’ College in Letchworth Garden City walked out in November over the plans.

Last week, members of the NEU teaching at 23 schools across the country under the Girls’ Day School Trust voted in favour of strike action to take place later this year, which would be the first strike in its 149-year history.