Six months before Brexit, the UK government is attacking the EU  

Jeff J Mitchell | Getty Images News | Getty Images

BIRMINGHAM, ENGLAND – SEPTEMBER 30: British Prime Minister Theresa May applauds as she sits in the audience during the annual Conservative Party Conference on September 30, 2018 in Birmingham, England. 

Liam Fox, Trade secretary and an outspoken Brexit supporter, told CNBC on Sunday that it is the EU’s “duty” to help the U.K. and put forward their proposals.

“They said they were not very happy with what the U.K. offered, in which case let them bring forward their own proposals,” he said.

“Under Article 50 (the legislation that allows a EU country to leave the Union), we have the right to leave the European Union and they have a duty to help us in that future relationship. Let’s see them now deliver what they promised to do in that treaty,” Fox said.

The U.K. government presented in July a plan for its future relationship with the rest of the European Union. But the latter argued that some of the proposals compromised key principles under European law.

European Council President Donald Tusk said in September that the so-called Chequers plan would not work. U.K. Prime Minister Theresa May has stood by her proposal despite such messages from the EU. She told the BBC on Sunday that her Brexit plan is not dead.

However, May also faces criticism over her plan inside her own party. Boris Johnson, the former foreign affairs minister, who is seen as a potential candidate to replace the prime minister as Conservative leader, said the Chequers plan is “deranged.”

David Lidington, cabinet secretary, told CNBC on Sunday that those who criticize the prime minister need to come up with “credible” alternative proposals.

“The key thing is to get the deal with the European Union because that’s what will protect jobs and the economic interests of people in this country and the integrity of the United Kingdom, Great Britain and Northern Ireland, then we go to parliament and we make the case,” he said.

“I think that our parliamentary colleagues at that point will have to face up to the fact there is a real decision about this country’s future to be taken, we have not yet had any credible alternative from those that are criticizing the Prime Ministers’ plan,” Lidington added.