Mrs May is said to be pouring over the plan, which “is for the whole UK to participate in a customs union with the EU”, and is a scenario that could take effect if no other solution to the Irish border question is found.
The plan would act as a temporary deal with the EU until a final solution to the Northern Ireland border enigma that has so far stifled Brexit negotiations is finally solved.
An unnamed source told the Financial Times that officials in Dublin “privately argue it could settle the border question and open the way to a deal”.
EU chief negotiator Michel Barnier has already rejected the idea, according to the FT source.
Irish Prime Minister Leo Varadkar and Barnier are meeting later today to discuss the border issue in depth.
The Irish border has been a massive stumbling block since Brexit negotiations began in the wake of the June 2016 EU referendum that saw 52 percent of Britain vote to leave the EU.
But a solution to the issue needs to be found before the UK leaves the bloc on 29 March 2019.
There had been suggestions that Northern Ireland could remain part of the EU’s customs union, yet the new plan Mrs May is said to be working on could see the rest of the UK also remain tied to EU trade rules and regulations.
This would scrap the need for tariffs on goods transported between the Irish Republic and the UK, and could even prevent the need for a hard border all together, as well as costly and complicated customs checks.
The temporary extension of the customs union would also prevent Northern Ireland being cast out of the UK.
It comes after Mrs May delivered a keynote speech at the Conservative Party conference, where she insisted Britain’s post-Brexit future is “full of promise”.
Mrs May said: “Those of us who do respect the result need to come together now if we don’t – if we all go off in different directions in pursuit of our vision of the perfect Brexit we risk having no Brexit at all.”