LONDON (Reuters) - Britain’s Brexit minister Stephen Barclay will hold a meeting of a new working group of Conservative lawmakers on Monday seeking to find an alternative plan to avoid a post-Brexit border in Ireland, Prime Minister Theresa May’s office said.

Last week lawmakers voted to support May’s Brexit deal if she could agree “alternative arrangements” to replace a controversial Irish border arrangement, known as the backstop.

The EU has so far ruled out reopening the exit deal to make any changes to the backstop, an insurance policy that aims to prevent the reintroduction of border controls between EU member Ireland and the British province of Northern Ireland.

May, whose deal was roundly rejected by parliament in January, won the support to seek changes to it thanks in large part to a peace accord between both eurosceptic and pro-EU factions within her divided Conservative Party.

May said she would work with the backers of the this strategy, dubbed the Malthouse Compromise, which courts Brexiteers with a promise to ditch the backstop and appeals to pro-EU Conservatives by pledging safeguards against the risk of disruption if no exit deal can be agreed.

“To take forward this work, the government is establishing an Alternative Arrangements Working Group which will hold regular meetings with Steve Barclay,” May’s office said in a statement.

The first meeting will take place on Monday, with further meetings planned for Tuesday and Wednesday, it said.

The group will be supported by officials from several government departments, and membership will include pro-Brexit lawmakers Steve Baker, Marcus Fysh and Owen Paterson, as well as pro-EU Conservatives Damian Green and Nicky Morgan.

May’s office said Attorney General Geoffrey Cox was also looking into the legal changes Britain is aiming to secure to the backstop, with ideas including a unilateral exit mechanism or a time limit.