GREEN MP Caroline Lucas has warned of a potential "collapse of law and order" if Brexit went ahead without a deal as Labour distanced itself from backing a second EU referendum.

Speaking at a People's Vote press conference in Westminster, she said: "The Government has not put 3,500 troops on stand-by to hand out plastic Union flags for everyone to wave at their no-deal Brexit street parties. It's put troops on stand-by to help deal with the potential collapse of law and order.”

The Brighton MP went on: "It is simply incredible that with just 66 days until we risk crashing out of the EU with no deal, the Prime Minister and her shambles of a Government are still prepared to entertain the social and economic catastrophe they know a no-deal Brexit would be."

In the case of no-deal, Ms Lucas also warned: “We don't know exactly how many roads in Kent will become a lorry-park, exactly which businesses will collapse, how many planes will be grounded, which shelves will be empty or indeed whether the streets of Northern Ireland will be safe."

She added: "It is unforgivable to be playing games with peace in Northern Ireland."

Earlier, after Labour tabled a Commons amendment allowing MPs to vote on ways to end the "Brexit deadlock," Rebecca Long Bailey, the Shadow Business Secretary, made clear it had been carefully written and did not tie her party into backing a People’s Votes "in any way".

It came as Theresa May held her weekly Cabinet meeting, which was set to be dominated by Brexit, including the possibility of giving Tory MPs a free vote on the issue of extending the Article 50 process, which some believe will get majority backing in next Tuesday’s Commons vote.

The proposal is now believed to be supported by Amber Rudd, the Work and Pensions Secretary and the Prime Minister’s close ally, who has urged Downing Street to allow Tory MPs a free vote on moves aimed at preventing a no-deal amid fears that dozens of ministers could otherwise resign.

Labour's amendment calls for a vote on Labour's plan for a customs union with the EU and whether or not to legislate "to hold a public vote on a deal or a proposition" that is supported by a Commons majority.

However, Ms Long Bailey insisted Labour was "prioritising" its own Brexit deal proposal.

"The amendment is very specifically worded to allow for the debate of the options. It is not stating that the party supports a second referendum in any way and indeed if it was passed, the amendment, and it went to a vote on the specific issues, then that would be a decision for the party to take at the time," she explained.

However, the MP for Salford and Eccles also described a backbench amendment tabled by her Labour colleague Yvette Cooper, designed to stop a no-deal Brexit, as "fantastic", suggesting the party could support it.

Earlier, Jeremy Corbyn said the option of a public vote should be considered, despite Mrs May's warning that it could "damage social cohesion", but he also made clear Labour’s preferred option of a customs union and a close relationship to the EU’s single market was now the primary one.

He explained: "Our amendment will allow MPs to vote on options to end this Brexit deadlock and prevent the chaos of a no deal.

"It is time for Labour's alternative plan to take centre stage, while keeping all options on the table, including the option of a public vote."

At the People's Vote event, Jo Swinson, the Liberal Democrat deputy leader, accused Jeremy Corbyn of showing a “dreadful lack of leadership" and Labour had been "riding both horses for far too long".

The MP for East Dunbartonshire said it was now clear Labour votes would be "pivotal" to the outcome of Brexit.

"Labour is at a point now where it has to choose," she declared. "The Labour leadership has been riding both horses for far too long. Labour can decide. Their votes will be pivotal. They can either make Brexit happen or Labour can stop Brexit. The time for decision is upon us," she added.

Meanwhile, it was suggested Tory HQ has been effectively put on a snap general election "war footing" due to the Brexit situation in Parliament.

Elsewhere, Conservative backbencher Dominic Grieve, the former Attorney General, has tabled an amendment allowing MPs to take control of parliamentary business a day every fortnight in February and then a day a week in March until Brexit day.

Backed by MPs from across Parliament, including Tory ex-ministers Justine Greening and Sam Gyimah and Labour's Chris Bryant and Chuka Umunna, it would allow debate of up to six-and-a-half hours and the motion, like that due to be laid next Tuesday, would be amendable.

However, the Buckinghamshire MP removed a controversial passage that would have allowed a motion by a minority of 300 MPs - from at least five parties and including 10 Tories - to be debated to allow for indicative votes on where to go next.

Earlier, a cross-party group of MPs, including Ms Cooper and former Conservative Minister Nick Boles, put down an amendment seeking to give time for a Bill to suspend the Article 50 withdrawal process if there were no new deal with Brussels by the end of February.

Labour's Hilary Benn has tabled an amendment to the Government motion calling for a range of indicative votes on various Brexit options.

He tweeted: "Just tabled an amendment for next week's Brexit debate calling for the House of Commons to hold a series of indicative votes on a way forward."

In a separate development, Karin Kneissl, the Austrain Foreign Minister, poured cold water on a suggestion by her Polish counterpart that the Irish border backstop, a key stumbling block in the Brexit deal process, could be time-limited.

She also dampened hopes of an extension to Article 50 to give the UK more time to negotiate, asking: "Where is the added value of the new British suggestion?"

Stephen Barclay, the Brexit Secretary, also suggested that European politicians might not all support an extension to Article 50 if the UK asked for one.

He told BBC Radio 4’s Today programme that there were "practical issues" over the European Parliament elections in May, adding: "From the EU point of view, they have been very clear that they don't want an extension with no purpose and so we come back to the issue as to what it is MPs are for and just what they are against."