One in five private school teachers got no pay rise this year and increases across the sector have lagged behind state schools, a survey has found.

Just 1 per cent of independent school teachers surveyed by the NEU got a pay rise that at least matched the 3.5 per cent recommended for maintained schools.

But 21 per cent of private school teachers and 15 per cent of support staff said they received no increase at all this September, the survey found.

The most common pay increases across the sector were between 1.1 per cent and 2 per cent.

“With pay awards lagging behind the state sector, this year could prove a watershed for many independent sector staff,” said Dr Mary Bousted, joint general secretary of the NEU.

“Frustration over pay, combined with growing confidence from our enhanced membership of over 30,000 working in the sector, means that more and more NEU members are getting organised at school level, and asserting their rights to collectively negotiate their pay and working hours.”

In July, education secretary Damian Hinds announced a 3.5 per cent increase for teachers in the main pay range, 2 per cent for the upper range and 1.5 per cent for leadership.

With inflation standing at 2.4 per cent at the time, the influential Institute for Fiscal Studies calculated that 60 per cent of teachers would suffer a real-terms pay cut.

Headteachers described Mr Hinds’ decision to go against the School Teachers’ Review Body’s recommendation to give all teachers a 3.5 per cent increase as a “kick in the teeth”.

The NEU said a 1 per cent rise every year since 2010 was the equivalent of a more than 14 per cent real-terms pay cut when adjusted for inflation.

But the union said workloads continued to increase, with over two-thirds of the more than 1,000 teachers surveyed saying they had more to do than last year.

More than four in 10 teachers in independent schools said they work every weekend, and a further three in 10 said they “regularly” do.

As one teacher in Scotland put it: “I regularly work from 7.30am to 6.30pm at school, plus an hour at home three evenings a week and every weekend.”

Increasing numbers of support staff (39 per cent) also reported their employers were now only paying them during term-time, when they were expected to work over-time without extra pay.