London schools are in the throes of a growing crisis in teacher retention, with figures revealing that more than four out of 10 quit the profession within five years of qualifying.

Schools across England say they are struggling to recruit and retain staff, but the problem is most acute in inner London where just 57% of teachers who qualified in 2012 were still working in the classroom by 2017.

According to new analysis of government figures by Labour MP Matthew Pennycook, of the 35,000 newly qualified teachers (NQTs) who started teaching in the capital since the Conservatives took power in 2010, more than 11,000 have already left.

Retention rates have deteriorated year on year since 2011. More than a quarter of teachers recruited to London schools in 2015 had already left the classroom by November 2017 and over a third of new London teachers now leave within four years.

Pennycook, MP for Greenwich and Woolwich in London, described the figures as alarming. “The crisis in teacher retention in London did not begin the day before yesterday, yet this Tory government still has no coherent plan to address the problem and no appetite to get to grips with the underlying drivers – workload, stagnant pay, rising living costs and a lack of genuinely affordable housing to rent and buy – that lie behind this worrying trend.”

The crisis in retention comes at a time of growing demand for school places and increasing pupil numbers, particularly in the capital. Earlier this year parliament’s spending watchdog, the public accounts committee (PAC), criticised the government for failing to do enough to persuade disenchanted teachers to stay in the profession.

Meanwhile, the school population continues to expand. The Department for Education (DfE) expects secondary school pupil numbers to go up by 19.4% between 2017 and 2025. The PAC accused the government of spending too much on training new teachers (£555m) and not enough (36m) on retaining and developing existing ones.

Angela Rayner, the shadow education secretary, said: “This is the latest evidence that the Tories have created a crisis in teacher recruitment and retention, yet ministers continue to bury their heads in the sand. The next Labour government will create a National Education Service, providing the funding our schools need and the pay our teachers deserve.”

Kevin Courtney, joint general secretary of the National Education Union, added: “Our own research shows that 81% of teachers have considered leaving the profession in the last year because of workload, driven in a large part by time-consuming data gathering that has little or nothing to do with children’s education.

“Real-terms pay cuts have put teaching far behind other graduate professions and, in London and other hotspots around the country, very high rents have also contributed to the problem. It is no surprise that, faced with this, teachers leave the profession.”

While retention rates were worst in inner London, only 74% of NQTs in the east Midlands and the north-east were still in service after five years. Nationally, NQTs from secondary schools were less likely to stay in the profession than those in primary or special schools and the subject with the lowest retention rate was modern foreign languages with just 56% still in the job after five years.

A DfE spokesperson said: “The education secretary has made clear his top priority is to ensure teaching remains an attractive and fulfilling profession. There are more than 450,000 teachers in our classrooms – 11,900 more than in 2011 – with increasing numbers returning to the profession.

“We want to continue attracting the best and brightest to the profession, so are working with teachers, school leaders, Ofsted and the unions to develop our recruitment and retention strategy and deal with issues like unnecessary workload, which can frustrate teachers.”