Two schools in in Theresa May's constituency have asked parents to donate £1 a day so they can afford stationery and books, as they have been hit by "national changes to school funding".

The Robert Piggott Church of England infant and junior schools in Wargrave, Berkshire – situated in the prime minister's constituency of Maidenhead – sent a letter asking parents if they could donate the equivalent of £190 a year so it could buy items such as pencils, pens, glue and books.

The schools blame recent Tory cuts for the shortfall in funding. Education secretary Justine Greening has announced a change in national funding for schools for 2018/19 which would resolve "unfair" and "inconsistent" funding levels.

However, the overall budget for schools would not increase, with the National Audit Office estimating schools would in fact face cuts of up to £3bn by 2020. Inner city schools in some of the UK's biggest cities – London, Manchester, Birmingham and Liverpool – could face the biggest cuts, while more funding will go to the suburbs and shire counties.

Education minister Nick Gibb said the schools in Berkshire are set to gain around £10,000 a year in extra funds from 2018 under the reforms.

The letter to parents, seen by the Mirror, read: "One of the elements of [the funding plan] was to ask parents and the community to consider making donations to help meet the predicted shortfall in funding.

"Therefore, like many other schools, we are now requesting voluntary contributions from parents.

"We would like to suggest that parents donate £1 per school day for each child to help the schools through this funding crisis. This equates to £190 per year."

Shadow education secretary Angela Rayner said the plea for donations is proof of how Tory cuts are "hitting schools badly".

Lib Dem education spokesperson Layla Moran added: "The harsh impact of school cuts are now being felt in the prime minister's own backyard.

"It beggars belief that in 21st century Britain, cash-strapped schools are having to ask parents to pay for basic equipment. It is undermining the state-funded schools system."

Sally Ann Aker, executive head of Wokingham council, who runs the schools, said: "Like many schools, we are ­experiencing rising costs in the face of reduced funding.

"Whilst committed to the principle of state-funded education we have reached the stage where we need to ask parents and the community to consider making voluntary donations to help meet the predicted shortfall in funding. This ­decision has not been taken lightly."

Theresa May school
Theresa May is greeted by pupils during her visit to Dunraven School in South London