Leading Tory Eurosceptic Jacob Rees-Mogg said dozens of Conservatives were steadfast in their opposition to Theresa May's Brexit plans.

At a Leave Means Leave rally in Torquay, Devon, Mr Rees-Mogg said: 'There are probably 39 Tory MPs who are more tough-minded on this issue than I am.

'I am not the most tough-minded among my friends in the Conservative Party, and those 39 will not turn, I will not turn and there are growing numbers beyond that who are determined that we should deliver on the Brexit that we promised.'

Left to right: Tim Martin, founder and chairman of JD Wetherspoon; MEP and former UK Independence Party leader Nigel Farage, and Conservative MP Jacob Rees-Mogg

He said 'the future of our country is at stake, the future of our party is at stake', and added: 'We are so nearly there, we must make sure that Chequers is binned, that this idea of a customs union, the sheer lunacy of paying £3.5 billion a year to subsidise the European Union for all eternity is binned.

'We are close, we are almost there, we just need to be steady for a few more weeks and if we do that the prize is there to be grasped.'

The speech at Torquay's Riviera International Centre on Chestnut Avenue comes as it emerged that the UK could remain tied to Brussels' rules beyond the end of 2020 to give negotiators more time to finalise a trade deal.

The possible extension of the transition period, which would see the UK remain in the single market and customs union, is being considered as negotiations continue ahead of a crunch summit in Brussels on Wednesday.

Under existing plans, reaching a Brexit deal would mean the transition period will last until the end of 2020, with the UK accepting Brussels' rules without having a seat at the table when they are decided.

Mr Rees-Mogg told a Leave Means Leave rally in Torquay that the Chequers plan must be 'binned', adding: 'We are close, we are almost there, we just need to be steady for a few more weeks and if we do that the prize is there to be grasped'

Pictured: Nigel Farage visits a cafe on a walkabout ahead of the 'Leave Means Rally' at the Rivera International Centre today

But a potential extension was under consideration to allow more time to draw up a deal on the future relationship between the EU and UK and avoid the need for a 'backstop' arrangement to circumvent a hard border in Northern Ireland, according to reports by the Guardian and Daily Telegraph.

The Department for Exiting the European Union said it would not comment on speculation.

Theresa May called the EU's solution to the backstop issue - which would see Northern Ireland remain aligned with Brussels' rules - unacceptable.

The Prime Minister's counter-proposal, which was set out in June, is for a 'temporary customs arrangement' for the whole UK.

Conservative Brexiteers are suspicious that this could become a permanent situation - restricting the UK's ability to negotiate trade deals around the world.

Brexit Secretary Dominic Raab said a provision on customs which was not 'finite' would fail to deliver the result of the 2016 referendum and Downing Street insisted that Mrs May would not agree a Brexit deal which would 'trap' the UK in a permanent customs union.