And pupils attending independent schools are twice as likely to hire a private tutor as their state-school counterparts, the survey of 1,607 teachers revealed.
The Sutton Trust charity, which commissioned the poll, is therefore calling for the government to introduce a voucher scheme to allow the poorest families to access extracurricular tuition.
The poll reveals that 43 per cent of state-school teachers have worked as a private tutor at some point during their teaching careers.
Teachers in the North-East of England were the most likely to have taken on tutoring work: 49 per cent had done so. By contrast, only 34 per cent of teachers in the North-West and Merseyside had taken on such work: the lowest proportion in the country.
These figures are published today in a new report, Shadow Schooling, published by the Sutton Trust. The report also reveals that the proportion of pupils receiving private tuition has risen by more than a third in the last decade.
The proportion of pupils receiving private tuition has risen from 18 per cent in 2005 to 25 per cent in 2016. In the last year, a tenth of all state-school pupils between the ages of 11 and 16 – around 280,000 students – received additional tuition.
And a quarter of pupils said that they had received private tuition at some point during their schooling. This rose to 42 per cent in London.
The most common reason for hiring a tutor, given by 47 per cent of those who had done so, was for extra support with school work. More than a third – 38 per cent – had recruited a tutor to help them with a specific GCSE exam.
Nearly a fifth – 18 per cent – hired a tutor to help prepare for grammar-school entrance exams.
Sir Peter Lampl, chairman of the Sutton Trust, said: “No-one wants to limit parents doing their best for their children, but we need to ensure that extra tuition is as widely available as possible. Otherwise, it will continue to widen the attainment gap.”
The cost of one hour with a private tutor is typically £24, rising to £27 in London, the Sutton Trust says.
The Trust therefore calls on the government to introduce a means-tested voucher scheme, to ensure that lower-income families have access to qualified private tutors.
The trust also recommends that tuition agencies provide a proportion of their services to disadvantaged pupils for free. Some agencies already do this.