A Conservative donor has threatened to stop giving money to the party if Britain.
Sir Andrew Cook from Hope Valley is made a Knight Bachelor of the British Empire by the Prince of Wales at Buckingham Palace.
Sir Andrew Cook, who has given more than £1.2 million to the Tories, told a national newspaper he would not be able to support the Prime Minister if she opted for a hard Brexit.
Sir Andrew, the chairman of a steel company, told the Times it would be “impossible” for him to continue with his financial support of the party if Mrs May took the UK out of the single market.
He said Britain would be “sleep walking to disaster” the Prime Minister chose to pull out of the EU completely in order to control the UK’s borders.
Sir Andrew is not the only Conservative donor to lose faith in the party ahead of EU negotiations.
Another key Tory backer said last night that he was experiencing “donor fatigue”, in a sign that the prime minister risks losing significant support from the City and industry.
Sir Andrew said the current crisis was the result of the “political dog wagging the economic tail”.
“The economic arguments of staying in the single market are overwhelming and I have yet to see any plausible alternative arguments being put forward to leaving the single market,” he said.
“It seems to me the political tail is wagging the economic dog.
“There appears to be a willingness to consider the sacrifice of withdrawal from the single market, which I believe will be a catastrophe.”
Sir Andrew is also the chair of William Cook, the UK’s largest manufacturer of steel casings, and is reliant on access to the EU.
He added: “I would find it impossible under those circumstances [to keep donating to the Conservative Party should it back leaving the single market] . . . It is very difficult to make a political donation to a party when, although I support it ideologically, I do not believe that my interests and my ideology are ad idem with the principal Brexiteers.”