A senior Labour MP has made the extraordinary claim that voting down the Article 50 Bill could lead to riots.

Matthew Pennycook, a junior Brexit spokesman, warned of “civil disturbances” by angry Leave voters if MPs blocked the referendum result.

The move would also lead to Theresa May calling, and winning, a snap general election – and forcing through an even harder Brexit, he said.

Mr Pennycook spoke out amid Labour turmoil over its leadership's support for the Article 50 Bill, which has reached the Commons today.

Two Labour frontbenchers have resigned, with Jeremy Corbyn accused of giving the Prime Minister a “blank cheque” to force through her version of Brexit.

But Mr Pennycook said of blocking Article 50: “It would exacerbate the divisions that the referendum has exposed, it would be a gift to the far right, it might even cause civil disturbances in parts of the country.

“I think people would take to the streets…that is a danger.”

The Brexit spokesman also urged unhappy Labour colleagues to recognise the danger of a general election if MPs stood in the way of the referendum result.

Speaking to the BBC, he added: “If Parliament voted down the Bill it would almost certainly trigger a general election that I think, in the current circumstances, would give the Government a majority.

“Going to the country on that sole issue of Parliament defying the outcome of the referendum would lead to and guarantee the hardest of Brexits.

“With the current balance of the Commons at the moment, we have a reasonable chance of ensuring that doesn’t happen.”

That last claim is strongly disputed by MPs who fear Parliament is about to trigger Article 50 with no means to impose checks on Ms May if the negotiations go badly.

The Liberal Democrats have said they will oppose the Bill unless Ms May agrees to a further referendum on the final deal – a call the Government will reject.

And Labour is demanding a “meaningful vote” in Parliament on the final Brexit deal – early enough for Ms May to seek better terms if hers are rejected by MPs.

The Prime Minister has threatened to crash out of the EU with “no deal” if Parliament rejects her terms – despite stark forecasts of an economic slump if she does.

However, Mr Corbyn has said he will tell Labour MPs to back the Bill even if Labour’s amendments are thrown out in a final showdown next week.

That stance will provoke further front-bench resignations, probably including the departure of Shadow Business Secretary Clive Lewis.

The Bill will be debated today and tomorrow, before a vote to give the legislation its second reading, which the Government will win easily.

That will be followed by three days of line-by-line scrutiny in a Bill committee, at which opposition parties will attempt to shape the Brexit process.