The former education secretary lashes out at colleagues – including ministers – who she said “talk tough” but who have “spent the past year saying now is not the right time to act”.
“It’s like standing by whilst a car crash happens and then expecting thanks for arriving with a first aid bag too late,” Ms Greening protests, in an article for The Independent.
It comes ahead of a likely Commons showdown on Tuesday aimed at preventing Boris Johnson – the near-certain next prime minister – from suspending parliament in October, to carry out a crash-out Brexit.
Pressure is growing on ministers who have spoken out against a no-deal to back a crucial amendment, tabled by Dominic Grieve – even at the cost of their jobs.
All eyes will be on chancellor Philip Hammond, David Lidington, the de-facto deputy prime minister, David Gauke, the justice secretary, Amber Rudd, the work and pensions secretary, and Greg Clark, the business secretary.
“There are ministers who profess to want to stop a no-deal,” Ms Greening said. “Well, tomorrow is when they can vote to do that and when they need to do it.
“This is a hugely serious situation. Not taking no-deal off the table has already cost jobs and that has to come first, doesn’t it?”
The ministers had been expected to sit tight until after Mr Johnson was in No 10, but, as one unnamed MP put it, “everyone knows Boris will sack them in a fortnight so they will have nothing to lose any longer”.
Ms Greening spoke out as Mr Grieve, the former attorney general, tabled his promised amendment to Northern Ireland legislation, which is expected to be selected by John Bercow.
If passed, the government would be required to update MPs every fortnight on progress being made in restoring the Stormont assembly – thus requiring the Commons to be sitting in the run-up to the 31 October Brexit deadline.
If Mr Johnson did prorogue parliament – something he has not ruled out – it would have to be recalled by the Queen in the similar way as required under the 2004 Civil Contingencies Act, amid a national emergency.
And, crucially, ministers would have to table an approval motion – which could then be amended by MPs to try to prevent the UK crashing out of the EU without a deal.
In her article, Ms Greening says of anti no-deal Tories: “After months of lots of robust words, whilst also sitting on their hands, they should now step up to the plate. It’s time to walk the talk.
“We won’t need an alternative parliament if MPs use the real one we already have. Who or what is stopping them? It’s simple – back up your words with action.”
Ms Greening, a supporter of a Final Say referendum, goes on to urge MPs to recognise they must also embrace a public vote, or recognise a general election as the only alternative.
She has not ruled out joining a vote of no confidence to stop a no-deal departure if necessary, but believes it can be avoided without reaching that point.
Nick Boles, the former Conservative MP who quit the party over its refusal to compromise on Brexit, immediately put his name to the Grieve amendments.
“Any MP who wants the House of Commons to be in a position to fulfil its proper constitutional function this autumn should support them,” he tweeted.
The prime minister’s spokesman declined to comment on the amendment ahead of seeing it, but can be expected to order Conservative MPs to oppose it by enforcing a three-line whip.
All Tory MPs have been ordered to cancel engagements and be in parliament on Tuesday, for committee stage and third reading of the Northern Ireland (Executive Formation Bill).
Earlier, Mr Grieve himself urged MPs to recognise that the chances of a no-deal Brexit were “very slim indeed” if “majority of the House of Commons” opposed it.
“Removing the possibility of prorogation makes them even slimmer,” he told Sky News.
Around 30 Tory MPs are believed to be exploring how to block crashing out – although the number willing to do so was put at 100 by Rory Stewart.
In a BBC Panorama programme tonight, the former top civil servant at the Brexit department admits a no-deal Brexit is something “everybody should be worried about”.
“We would be taking a step into the unknown,” Philip Rycroft said: “We would be taking a step into the unknown.
“It’s not in the UK’s interest to have no-deal, it’s not in the EU’s interest to have a no-deal,” said the man in charge of Brexit planning for 18 months before stepping down in March.
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