FILE PHOTO: Britain's former Brexit Secretary David Davis talking on the Marr Show on BBC television in London, Britain, September 2, 2018. Jeff Overs/BBC/Handout via REUTERS

LONDON (Reuters) - Opponents of British Prime Minister Theresa May’s Brexit proposals within her Conservative Party will set out an alternative plan soon, her former Brexit minister will say on Thursday.

David Davis, who resigned in July in protest at May’s ‘Chequers plan’ for leaving the European Union, will say it breaks a promise made by her to return control over law, money and borders to Britain.

“The Chequers plan crosses on all of those red lines,” he will say in a speech to the Hanns Seidel Foundation in Munich, according to advance extracts. “...Chequers is devoid of democracy altogether.

“This is why many of us will shortly be presenting an alternative plan which will outline a more ambitious vision.”

Opponents of May’s plans for Britain to remain in a free trade zone for goods with the EU have faced criticism for attacking them without offering an alternative.

Last week the anti-EU European Research Group (ERG) of Conservative lawmakers set out their proposals for solving the issue of the Irish border, one of the remaining sticking points in Brexit negotiations.

British newspapers reported that the group had circulated a broader 140-page alternative plan but then shelved it.

With just over six months until Britain is due to leave the EU, May urged fellow European Union leaders at an informal summit on Wednesday to follow her lead and adapt their Brexit negotiating stance to secure a good deal.