The Prime Minister was engaging in an urgent round of telephone diplomacy in the wake of the High Court decision which insisted Parliament must have the final say on Britain triggering divorce deal negotiations with Brussels.
Mrs May is calling European Commission president Jean-Claude Juncker on Friday in a bid to persuade continental leaders that the explosive legal ruling would not shake her from the pledge to invoke Article 50 of the Lisbon Treaty - which would formally launch Brexit - by April next year.
But the uncertainty created by the High Court judgment was underlined by Tory former chancellor and ardent pro-European Ken Clarke, who told BBC Newsnight he would move to block invoking Article 50, saying: “I will vote against it. I shall stick to my guns. I’m not going to cast a hypocritical vote.”
With the largely pro-EU Commons in the Brexit driving seat pending an appeal of the High Court ruling to the Supreme Court in early December, interim Ukip leader Nigel Farage called on Mrs May to call a snap general election, even though he said such a move would face stiff opposition from Tory and Labour benches alike.
The move came as Communities Secretary Sajid Javid gave a scathing response to the judgment as he branded it “unacceptable”.
Asked on BBC Question Time if the High Court ruling flew in the face of democracy, Mr Javid said: “Yes, it does.”
He added: “This is an attempt to frustrate the will of the British people, and it is unacceptable.”
Writing in the Daily Telegraph, Mr Farage said: “The best thing Theresa May could do now would be to call a general election, but it is unlikely that Labour MPs, led by a man they don’t believe in, would be keen on facing the likely electoral oblivion that would follow. It also seems likely that some on the Prime Minister’s own backbenches, who are seeking to overrule the will of the British people, would be unlikely to support an early general election either.
“The establishment, in denial after the referendum result, still just don’t get it. The British people are not simply going to let this incredible establishment arrogance lie. I suspect even more radical political change is on the way.”
Under the Fixed Term Parliament Act brought in by the Tory-Liberal Democrat coalition, the slated May 2020 general election could be brought forward only if two thirds of MPs vote for it or the Government loses a vote of no confidence and other parties cannot form an alternative administration within 14 days of such a move.
After the High Court ruling rocked Westminster, Brexit Secretary David Davis conceded that an act of Parliament would now be needed to trigger Article 50, with Mrs May’s spokeswoman stating his view was the “logical conclusion” to draw from the High Court judgment.
The spokeswoman said Mrs May was keen to tell other European leaders she would stick to the declared timetable for withdrawal, stating: “She will set out what the process is, which is that we are appealing and that we are carrying ahead and sticking to the timetable we have set out. This judgment is not going to derail that.”
Shadow foreign secretary Emily Thornberry told the BBC: “I think that Article 50 is going to happen. I think that in the end Parliament will vote for Article 50 to be triggered. But the really good thing about this judgment ... is that the Government will need now to come to Parliament and actually give us some basic terms on which they are going to negotiate Brexit. We do not allow the executive a free hand.”
Mr Juncker’s spokesman made it clear to reporters in Brussels that the phone call was taking place at the request of the Prime Minister, not Brussels.
Despite his opposition to triggering Article 50, Mr Clarke said he was “pessimistic” and expected the referendum to result in Britain’s exit from the EU.
In a sign of the difficulties the Government could face in getting legislation through Parliament - especially the Lords, where the Tories do not have a majority - a Conservative peer said Mrs May’s deadline of triggering Article 50 by the end of March looked like “an impossible target”.
Baroness Wheatcroft told the BBC Radio 4 Today programme: “I think that it’s only right to delay triggering Article 50 until we have a clearer idea of what it actually entails and I think there will be others in the Lords who feel the same way.
“How many it’s hard to say, but I think there could be a majority who’d be in favour of delaying Article 50 until we know a little more about what lies ahead.”
German MEP David McAllister, a member of Chancellor Angela Merkel’s CDU party, told Today: “I think it is important that we have clarity. The Prime Minister announced that she will trigger Article 50 in March 2017 and we should try and keep to this timetable because the two-year period should end before the next European elections, so we then have clarity if the UK will leave the European Union or not.”
He added: “The general mood in Germany is we would prefer the UK to remain part of the European Union. The Brits are very good friends and partners and neighbours for us, but we have to face reality and it was a narrow majority of the British people who decided to leave and that is what the Government is going to do.
“Chancellor Merkel said in the Bundestag once ‘there is no need to be nasty’. That means there is no need to punish the British, but on the other hand there is no need for favourable treatment. We have got to be firm on our principles, the UK Government have their own interests, let’s find a good deal.”