Around one in five teachers (18%) expect to leave the classroom in less than two years while two-fifths of teachers, school leaders and support staff want to quit in the next five years – blaming “out of control” workload pressures and “excessive” accountability, according to a poll by the country’s biggest teaching union.

Despite recent government attempts to address teachers’ concerns, 40% who took part in the survey predict they will no longer be working in education by 2024.

Ministers will be particularly worried about a potential exodus among recently trained teachers after the poll by the National Education Union (NEU) found that more than a quarter (26%) of those with less than five years’ experience plan to quit by 2024.

Of those with less than two years’ experience, whose careers have barely begun, the figure was still 15%. When asked the reasons why they planned to leave, respondents blamed workload (62%) and the accountability regime (40%), amid complaints about the pressures of Ofsted inspections and school performance tables.

“My job is no longer about children,” one respondent said. “It’s just a 60-hour week with pressure to push children’s achievement data through.”

Many of those who took part in the survey, which was self-selecting, provided vivid accounts of the impact their work has on their everyday lives. “Working 70 hours a week for many years has meant my health and family life have suffered. I am getting out before the job kills me,” said one.

“My personal life doesn’t exist anymore,” said another.

“With a young family, and despite working part-time, I have come to realise that a job in education is not conducive to family life,” another NEU member contributed.

The education secretary, Damian Hinds, announced plans in January to try to ease workload and help more teachers to job share, in an attempt to prevent experienced staff from leaving the profession.

The NEU joint general secretary Kevin Courtney accused the government of doing little more than “fiddling at the edges” in its attempts to address teacher workload. “So long as the main drivers of a performance-based system are still in place, schools will continue to be in the grip of a culture of fear, over-regulation, and a lack of trust,” he said.

“We need drastic action and a major rethink from government if we are to stop the haemorrhaging of good teachers from the profession.”

The NEU, which is holding its annual conference in Liverpool, is due to discuss workload, excessive working hours and bullying on Tuesday, with calls for the union to set aside a budget to take cases of workload breaches to tribunal and a national day of action to publicise the effect on children’s education.

One of the conference delegates, Henry Emoni, a maths teacher from Canvey Island in Essex who has been teaching for six years, said pressures had grown with class sizes up by around 10 pupils, fewer support staff, pressure to do holiday classes and fewer experienced colleagues to offer support.

Of the 30 colleagues he trained with, only four are still teaching in the UK. He said some had quit education, but others were teaching abroad in Dubai and the United Arab Emirates. “I think about leaving on a daily basis. I would like to learn from more experienced teachers, but there’s no one around.

The poll of 8,600 teachers, school leaders and support staff found that 56% felt their work-life balance had got worse or much worse in the past year, compared with 31% who said it was unchanged and 12% who saw improvements. Worst affected were senior leaders, heads of department and middle leaders, 66% of whom complained their work-life balance had deteriorated.

Responding to the survey, a Department for Education spokesperson said: “We have worked with school leaders and teachers to create a workload reduction toolkit, which provides practical advice and resources that schools can use rather than creating new ones from scratch.

“We are also tackling excessive data burdens in schools, simplifying the accountability system to target the associated burdens and working with Ofsted to ensure staff workload is considered as part of a school’s inspection judgement.”

When contributors to the survey were asked “what would be the one thing that would make your job better in the next 12 months?” responses were dominated by calls for a reduction in workload, with widespread complaints about heavy marking and over-assessment.

One respondent said: “Less assessment for pupils; it creates too much pressure on pupils and creates too much marking for teaching, which is taking away from valuable lesson planning, which would be much more beneficial for pupils.”

“Trust being given back to the teachers,” said another. “Less paper pushing and more focus on the children. Less emphasis on SATs results.”