Theresa May urged to trigger Article 50 ASAP amid fears it can be REVERSED

THERESA MAY has been urged to trigger Article 50 of the Lisbon Treaty as soon as possible amid fears it could be REVERSED at a later date by pro-EU MPs.

The Prime Minister, who has vowed not to invoke the legal mechanism for exiting the EU before 2017, has been told to complete Britain’s departure from the bloc before the next general election.

Once Article 50 is activated there is a two-year timeframe before a member state officially ceases to be part of the EU.

The warning to Mrs May to hurry up and get on with the process of exit negotiations comes amid concerns the two-year waiting period could be allowed to straddle a general election.

Both EU law experts and top lawyers have said there is “nothing in the wording” of Article 50 to rule out a departing member state changing its mind even if the clause has already been enacted.

It opens up the possibility of a government less committed to Brexit, or ardently pro-EU, being able to U-turn on the leaving process if elected before Britain’s departure is complete.

Influential Conservative backbencher and Brexit supporter Jacob Rees-Mogg told Express.co.uk: “It is essential that Brexit is completed before the next election as an incoming government could potentially withdraw an Article 50 request.

“The earliest part of 2017 seems the right time to pull the trigger in the expectation that we would be out of the EU by 2019 with an election the following year.”

And just days after the Leave vote on June 23, Liberal Democrat leader Tim Farron vowed to fight the next general election with a promise to keep the UK tied to Brussels.

A leading peer has already threatened to delay the triggering of Article 50 by encouraging the House of Lords to withhold its approval, if the High Court rules Parliament is obliged to be consulted on beginning the exit process.

A legal challenge to the Government’s insistence Mrs May does not need Parliament’s authorisation on Article 50 will be heard later this year, adding to worries Brexit could be bogged down in the courts.

It is essential Brexit is completed before the next election as an incoming government could potentially withdraw an Article 50 request.

Tory MP Jacob Rees-Mogg

Earlier this year, top EU lawyer Professor Derrick Wyatt QC told the House of Lords’ EU Committee that Article 50 could legally be reversed.

He told the group of peers: “There is nothing in the wording to say that you cannot. It is in accord with the general aims of the Treaties that people stay in rather than rush out of the exit door.”

He added: “Analysis of the text suggests that you are entitled to change your mind.”

Fellow top lawyer, Sir David Edward QC, told the same committee on the issue of reversing a decision to quit the EU: “It is absolutely clear that you cannot be forced to go through with it if you do not want to: for example, if there is a change of Government.”

There is no explicit mention of whether a decision to leave the EU can be reversed within the two-year timeframe for exit granted by Article 50 within the wording of the treaty.

Professor Tamara Hervey, an academic of EU law at the University of Sheffield, told Express.co.uk this meant it was “legally arguable either way” whether a decision to invoke Article 50 could be reversed.

She added: “Like so many aspects of Brexit, this is surrounded by uncertainty.”