The National Audit Office (NAO) has warned that the so-called ‘divorce bill’ the government has promised to pay the EU could be billions of pounds higher than estimated.

Prime Minister Theresa May had suggested British taxpayers will fork over £35-39 billion to the EU as the price of Brexit — despite having put tens of billions more into the bloc than it has received from it over four decades — based on an agreed formula.

But the NAO has warned that “the EU commission could skew future decisions” in order to significantly increase that sum, The Telegraph reports.

“The estimate reflects a number of moving parts, so the range of costs in it could have been wider than £35 billion to £39 billion,” observed Sir Amyas Morse, the head of the NAO.

The NAO also noted that the government estimate is not inclusive of a £2.9 billion commitment to the European Development Fund, which tops up Britain’s massive foreign aid budget.

No wonder they want to extract a massive Brexit bill… https://t.co/3RWsTHTsv4 — Breitbart London (@BreitbartLondon) November 23, 2017

“Ministers must make sure the EU cannot force the financial settlement to be higher and should be working to lower it as much as possible,” commented Priti Patel MP, the Brexit-supporting former International Development secretary.

“We’ve already paid hundreds of billions of pounds into the EU and the British taxpayer has had enough of the EU ripping us off.”

Former Brexit Minister Warns of ‘EU Sellout’, Predicts Divorce Bill Could Rise to £100 Billion https://t.co/m9jd9GdaVq — Breitbart London (@BreitbartLondon) December 10, 2017

Last year, former Minister of State at the Department for Exiting the European Union David Jones MP, who led the Welsh arm of the Vote Leave group during the EU referendum, warned that the Brexit bill could, in fact, rise to as much as £100 billion, amid rumours the public were being sold low-end estimates based on the obscure “formula” agreed by May’s negotiators.

“‘Government sources’ were quoted saying the price tag was likely to be £39 billion – down from an earlier-reported £50 billion,” he observed.

“However, the deal document contains no such precise figure, reduced or otherwise.

“What it does contain is a set of highly technical mechanisms we would have to follow to work out the eventual Brexit cost to the UK.

“And those mechanisms could land us with a bill, on some estimates, of as much as £100 billion – a figure EU sources were touting earlier this year.”

Follow Jack Montgomery on Twitter: @JackBMontgomery