British Prime Minister Theresa May’s Brexit proposals are the only “credible and negotiable” ones, her spokesman said on September 12.

“We have been working on the issue of the Northern Irish border for two years and we have looked at a significant number of potential solutions and we believe that the plan put forward by Chequers is the only credible and negotiable one,” the spokesman told reporters. The statement was in response to alternative proposals tabled by rebels in May’s party.

As reported by Deutsche Welle (DW), Germany’s international broadcaster, opponents to May’s plans for exiting the EU appeared to back down after reports 50 lawmakers discussed how to oust her. More proposals for the Irish border saw the light of day.

Hardline Brexiteers lined up on Wednesday to pledge their support for the British prime minister after reports of a dinner the night before when about 50 of them openly discussed a change of leadership.

In a radio interview on September 12, Environment Secretary and Brexiteer Michael Gove urged Conservatives to get behind May, who he said was “doing a brilliant job” negotiating Brexit.

However, a major sticking point in the negotiations is how to agree for a British withdrawal from Europe without reinstalling a hard border between the UK province of Northern Ireland with the Republic to the south.

On September 12, the main Brexit group in parliament, known as the European Research Group (ERG), announced its proposal for dealing with the issue. Customs declarations could be made ahead of travel, and goods could be inspected before they were shipped, the ERG suggested.

According to DW, similar proposals have been rejected by the UK government in the past.

“We have been working on the issue of the Northern Irish border for two years,” May’s spokesman said on September 12. “We have looked at a significant number of potential solutions and we believe that the plan put forward by Chequers is the only credible and negotiable one.”