In May's speech at the Conservative party conference in Birmingham, the prime minister finally offered more detail on the matter of Brexit, saying the UK would trigger Article 50 before the end of March next year, while speaking of a desire to introduce immigration controls and withdraw from the jurisdiction of the European Court of Justice (ECJ).
"Let me be clear, we are not leaving the European Union only to give up control of immigration again and we are not leaving only to return to the jurisdiction of the European Court of Justice."
May's comments look certain to put her on a collision course with many pro-EU conservatives, who have warned against the so-called hard Brexit, amid fears such an approach is likely to see the UK bundled out of the single market.
PM May's declaration brings welcome clarity on start of Brexit talks. Once Art. 50's triggered, EU27 will engage to safeguard its interests— Donald Tusk (@eucopresident) October 2, 2016
The Prime Minister of Malta, Joseph Muscat, who will hold the EU presidency during the triggering of Article 50, backed up these single market fears, tweeting that while Malta would be "honest brokers for fair deal," the four single market freedoms — which includes the freedom of movement — "cannot be decoupled."
Meanwhile, many pro-EU figures in May's Conservative Party almost immediately moved to criticize the PM's insistence on immigration being a priority in Brexit discussions.
"At the moment it looks like it's more in favor of tackling immigration than the single market," said former education secretary Nicky Morgan.
"Throwing access to the single market away because immigration is part of the negotiation would be a big mistake. It would damage the economy, and that damages all of us."
Hard Brexit: 'Total Abandonment and Recklessness'
The tension on May seems to be building, with a number of other Conservative Party members keen to remain in the European single market vowing to resist Theresa May's plans for what they call a "harsh Brexit."
"We would be reckless if we did not challenge some of the consequences of a hard, or harsh, Brexit. Because we have got to understand that, if it is a hard Brexit, it is also a harsh Brexit," MP Neil Carmichael said at a meeting of the Conservative Group for Europe, which was attended by around 80 conservative lawmakers.
"We must avoid, at all costs, a Brexit that damages our economy, damages our capacity as a nation to perform capably in the future and actually damages Europe."
Taking aim at May's "total abandonment and total recklessness", Carmichael added: "The Conservative Group for Europe has a job to do. The key thing to have in our minds is that our national interest matters."
The backlash comes at a difficult time for the prime minister, who was under pressure from both Leave and Remain forces in her party to reveal her hand and be clearer about the Brexit path she was willing to take.
While pro-Leave MPs and ministers have urged the PM to honor the results of the June 23 referendum and make a substantial change to the UK's relationship with the EU, others fears doing so would be hugely detrimental to the UK's economy.