Labour shadow foreign secretary Emily Thornberry took a swipe at Theresa May yesterday, warning that she didn’t “have enough authority” to lead Britain through the Brexit process.

Ms Thornberry made the comments on Sky News after the PM suspended two rebel Tory MEPs who behaved “totally irresponsibly,” according to a government source.

Ms May withdrew the party whip from South West MEP Julie Girling and South East MEP Richard Ashworth after they supported a resolution in Strasbourg declaring that “sufficient progress” had not been made in the Brexit talks to be able to move on to discussions about a future partnership.

Brexit Secretary David Davis has written to Labour leader Jeremy Corbyn calling on him to suspend 18 Labour MEPs who backed the motion on Tuesday that was passed by 557 votes to 92.

Last week, 30 Tory MPs led by former party chairman Grant Shapps were said to be plotting to get rid of Ms May following the bungled June election and her humiliating speech at conference.

Foreign Secretary Boris Johnson had also set out his own “red lines” for the Brexit talks on the eve of the conference, further undermining Ms May’s authority.

Ms Thornberry also told Sky News’ Sunday: “It doesn’t really matter who their leader is, they don’t know which way they are going, they don’t know what it is that they want to achieve.

“There’s definitely a chunk of them that want to have no deal at all, which would be definitely contrary to British interests.”

Ms May said during her speech that the government was preparing for the possibility of leaving the EU without a deal.

Her attempt to instil discipline comes as EU officials in Brussels have increased contact with Labour in preparation for a future change in government, according to The Daily Telegraph.

Ms Thornberry said Labour had always had conversations with the EU and that they had a clear position on Brexit.

Leaders are to decide at a European Council meeting on October 20 whether enough progress has been made on issues, including the financial settlement, to move on to other matters.

European Commission chief Jean-Claude Juncker has declared it would take a “miracle” for the leaving fee to have been agreed by then.