Britain's Prime Minister Theresa May and her husband Philip leave church in her constituency near Reading, Britain October 8, 2017. REUTERS/Peter Nicholls

BRUSSELS (Reuters) - Britain’s ruling Conservatives barred two of their own lawmakers in the European Parliament after they broke the party whip and voted for a motion demanding London do more to meet EU demands in Brexit talks.

“Julie Girling and ... Richard Ashworth were suspended from the Conservative Party last night after supporting a resolution ... to block Brexit talks moving forward,” the party said on Sunday in a statement that highlighted divisions over Britain’s move to quit the European Union in 18 months.

Prime Minister Theresa May supported the move. A government source said the two had behaved “totally irresponsibly”.

“They left the party no choice but to act,” Ashley Fox, leader of the 20-strong group, said in the statement, describing the decision of Ashworth and Girling, a former group leader and chief whip respectively, as “extremely regrettable”.

Girling, who like Ashworth and Fox opposed Brexit during last year’s referendum, defended her decision to vote with the overwhelming majority in Strasbourg on Tuesday on a non-binding resolution which urged EU leaders not to accept London’s request for talks on post-Brexit trade without further concessions.

“I did not vote to prevent trade talks,” she said, noting she called for such negotiations. However, she said in a statement that it was “patently obvious” that the EU’s test of “sufficient progress” on key divorce issues were not yet met.

Her vote, she said, put the interests of her constituents over party discipline and referred to support on the far-right for Britain to walk out without a deal: “I have never agreed to silently acquiesce as our country heads towards a cliff edge,” she said, describing that as “wanton economic self-harm”.

May, who also opposed Brexit, is battling to contain in-fighting over approaches to Brexit and threats to her leadership after an uncertain party conference performance last week.

Her Brexit minister David Davis is due back in Brussels this week for further talks. The party statement said Davis had written to leaders of the Labour and Liberal Democrat parties to complain after most British MEPs voted with the majority. He urged Labour leader Jeremy Corbyn to suspend most of his MEPs.