Sir Keir Starmer has been accused of “fudging the facts” about his education by the founder of a social mobility charity by suggesting that he attended a state school.

Sutton Trust founder Sir Peter Lampl, who went to the same school as the Prime Minister, Reigate Grammar, made the claim as he lambasted the Government for its plans to charge VAT on private school fees.

The school was funded by the local council when the Prime Minister joined – but became a private school two years into his time there.

Sir Keir received a bursary from the council to continue his studies until sixth form, as did other pupils who began attending the school before it was converted.

Sir Peter was an adviser to the Blair government on education and until last year was chairman of the Sutton Trust, a charity which aims to improve social mobility.

Writing for The Telegraph, he said: “I don’t pretend the school we went to was a state school, Starmer does. But he is fudging the facts.

“I am helping young people to benefit from an education that made all the difference to me, Starmer is destroying the opportunities to have the same chances he had.”

Sir Peter also claimed the “regressive” decision to charge the tax on school fees would deprive children of extra-curricular activities, “vandalising” the private sector.

Rather than taxing private schools, the Prime Minister “should be finding ways to better exploit and share what they have”, and “to open them up to a wider demographic”, he wrote.

In past references to his school, Sir Keir has described Reigate as a grammar school rather than emphasising that it is now a private one, and has also made much of his “working class background”.

Introducing VAT on private school fees is aimed at raising more money to fund state schools.

Schools in the state sector are faced with crumbling buildings made from Raac (reinforced autoclaved aerated concrete), there are staffing shortages, and headteachers are faced with increasingly tight budgets.

A Government spokesman said: “Ending the VAT break for private schools means an additional £1.7 billion a year that can be invested in our state schools, where 94% of this country’s children are educated.

“This means more teachers, higher standards and the best chance in life for all our children, as we deliver on our plan for change.”

Express.co.uk has contacted No.10 about Sir Peter’s remarks.