LONDON (Reuters) – The leader of the Northern Irish party propping up Britain’s government on Wednesday joined forces with the UK’s trade minister and two former Brexit ministers to call for an overhaul of the Irish backstop in the Brexit divorce deal.

Democratic Unionist Party leader Arlene Foster, trade minister Liam Fox and former Brexit ministers David Davis and Dominic Raab proposed changes to the backstop in the withdrawal agreement that British Prime Minister Theresa May agreed with other European Union leaders last month.

“The UK needs a unilateral exit mechanism from the backstop, but we can give the Irish government assurances that we would put in place specific measures to guarantee no return to a hard border,” Raab said in a joint statement.

The backstop aims to ensure there is no hard land border between British-ruled Northern Ireland and the Irish Republic, which is an EU member. But many UK lawmakers fear the backstop will leave Britain subject indefinitely to EU rules, long after the country has given up a say in drafting them.