Theresa May has vowed to Tory grassroots activists that she will not allow the referendum vote to leave the EU to be frustrated.

In a speech to the National Conservative Convention (NCC) in Oxford on Saturday, the Prime Minister told supporters the Government’s focus on delivering Brexit must be “absolute”.

Her comments came after three pro-EU Cabinet ministers signalled they could back moves in Parliament to delay Britain’s withdrawal to prevent a “disastrous” no-deal break.

The intervention by Amber Rudd, Greg Clark and David Gauke led to calls for their resignations by furious Tory Brexiteers.

Brexit
Amber Rudd is one of three Cabinet ministers to have signalled they could back moves to block a no-deal Brexit (Stephan Rousseau/PA)

But in her speech to the NCC, Mrs May also made clear the party must remain a “broad church” and there must be no “purges” of MPs because of their views on Brexit.

Her address comes as MPs prepare for a potentially crucial series of votes on Wednesday which could see Parliament seize control of the Brexit process if Mrs May cannot secure an agreement with Brussels by mid-March.

Writing in the Daily Mail, Work and Pensions Secretary Ms Rudd, Business Secretary Mr Clark and Justice Secretary Mr Gauke said it is clear a majority of MPs would support an extension to the Article 50 withdrawal process rather than see no deal.

However in her address to the NCC, Mrs May insisted it is vital the Government maintains its focus as the negotiations reach their final stages.

“Our focus to deliver Brexit must be absolute,” she told the behind-closed-doors meeting, according to extracts released by No 10.

“We must not, and I will not, frustrate what was the largest democratic exercise in this country’s history. In the very final stages of this process, the worst thing we could do is lose our focus.”

But after the resignations of three Tory MPs to join a group of Labour defectors in the new Independent Group, Mrs May said there should be no moves to deselect MPs because of their views on Brexit.

Anna Soubry, Heidi Allen and Sarah Wollaston all complained they had been targeted in their constituencies because of their pro-Remain views, in some cases by former Ukip members who had switched to the Tories.

However Mrs May said: “No-one gets more frustrated than I do when people vote against the whip, particularly given the tight Parliamentary arithmetic that we face.

Independent Group MPs
Sarah Wollaston, left, Anna Soubry, centre, and Heidi Allen have left the Tories for the new Independent Group of MPs (PA)

“But we are not a party of purges and retribution. We called a referendum and let people express their views – so we should not be seeking to deselect any of our MPs because of their views on Brexit.

“Our party is rightly a broad church – on that and other issues. And we will only save our country from the threat of Jeremy Corbyn if we remain one.

“So while I know it hurts to lose a fellow Conservative, our reaction has been the right one. To listen to their reasons, even if we disagree with them. To explain politely where we think they’re wrong.

“To respect the sincerity of their decision, even if we regret it. And to hold our nerve, keep our promises – delivering the best we can for the country we love, and putting the national interest first.”