Ed Davey, a Liberal Democrat leadership contender, has written in The Guardian calling for a government of national unity to “halt Brexit”. It’s a sensible argument, in theory.

A government of national unity could be what finally breaks through the Brexit gridlock. But Davey is wrong about who should lead this government, and on the limits of their policy platform, which he believes should be restricted solely to delivering a referendum.

For a unity government to work, it would need to be led by someone well-liked and trusted within Westminster and with the public. They would need experience working with MPs across party lines. Labour MPs are unlikely to back either a Conservative Remainer or a Liberal Democrat after the coalition’s austerity agenda contributed to the Brexit vote.

Of course, Conservative Remainers are unlikely to vote down their own government, triggering an early general election while Brexit remains unresolved. Many MPs are also concerned about doing anything to put Jeremy Corbyn into Number 10. But if they felt they could pull the plug on the government safe knowing it would not lead to either of those events, they might just do it.

Britain Before Brexit: East Midlands Show all 12 1 /12 Britain Before Brexit: East Midlands Britain Before Brexit: East Midlands Leicester There’s a great suspicion about homelessness in Britain: those desperately in need of social help feel the need to justify exactly why they are in their situation and exactly what they would do with your money Richard Morgan/The Independent Britain Before Brexit: East Midlands Loughborough A student dressed as a horse, drunk, headless, betting on the races: a human imitating for fun the animals that race for human entertainment Richard Morgan/The Independent Britain Before Brexit: East Midlands Loughborough A rock’n’roll evening where couples lead and are led. Twentieth-century American pop culture reaches far, well into this Loughborough periphery Richard Morgan/The Independent Britain Before Brexit: East Midlands Derby Beauty treatment centres appear both surgical and sacrificial from the inside. The woman’s horizontal body stretching across the three windows, sawn into thirds, and the beautician studies with her eyes the eyes she’s beautifying Richard Morgan/The Independent Britain Before Brexit: East Midlands Derby Two pairs of hands marked by anti-vandal paint, revealing the crime and the attempt to wipe it away, as if it never happened: the traces of a cover-up Richard Morgan/The Independent Britain Before Brexit: East Midlands Boston The search for a lost cat in a pub window, translated into Russian, extending the plea to the town’s Russian reading community in an effort to widen the net and increase the chances of a happy ending Richard Morgan/The Independent Britain Before Brexit: East Midlands Boston A warning to keep distance on the back of a white van, to give room, to respect personal space. A crude depiction of the female body occupies the foreground, the British flag and a church tower occupy the distance Richard Morgan/The Independent Britain Before Brexit: East Midlands Derby A circus decorated with British and English flags, probably to confer a sense of style and national pride that would attract more people. It’s a timely meeting of the circus and the nation, where performance, danger, trickery, and foolishness all come together to form the spectacle Richard Morgan/The Independent Britain Before Brexit: East Midlands Boston Polish football and regional graffiti is everywhere in Boston, if you’re looking for it. This vow of loyalty to Lechia Gdansk I find behind a supermarket carpark, between two trees goalpost-like, framing the inscription Richard Morgan/The Independent Britain Before Brexit: East Midlands Leicester A Catholic church on the New Walk, in which a man prays on his own, watched by Christ, solitary among empty chairs, committed, purified, sanctified Richard Morgan/The Independent Britain Before Brexit: East Midlands Boston Following the Rover Witham to the Marina and derelict rowing club, this anti-establishment expression catches my eye. It seeks to dehumanise authority, to make the law dirty, and connect power, not the people, to social filth. Richard Morgan/The Independent Britain Before Brexit: East Midlands Grantham The back of the Isaac Newton Shopping Centre, by the Bus Station, where a sign advertises a news-seller with images of Polish newspapers, and next, across the black dividing line, a racist scribble with little meaning at all. Richard Morgan/The Independent

MPs would achieve this by passing a motion of no confidence in the government. Parliament would then have two weeks to find another executive. In this time, MPs could install a cross-party government with the sole aim of holding a second Brexit referendum. If they are unable to form another government, a general election would take it out of their hands.

The leader, whoever that may be, would also need to win the votes of most of the shadow cabinet, so they will need to have avoided publicly clashing with Corbyn. This rules out both of Davey’s preferred options – Hilary Benn or Yvette Cooper. It would have to be someone who has not alienated those within the Remain coalition. And that person is Caroline Lucas.

The Green MP has long been the favoured face of the People’s Vote campaign. She is credited with forging the campaign in the days after the referendum result and has represented its aims in both post-referendum Brexit TV debates. But she has not ignored those who voted to leave in 2016, launching her “Dear Leavers” project to engage with those concerned about our membership of the European Union. She has credibility on both sides of this divide that many others do not.

Lucas also negotiated the successful Liberal Democrats/Green Party alliance in the 2016 Richmond Park by-election. This kick-started the Progressive Alliance movement in 2017. She has experience working with other parties that few could rival.

This would not be without precedent. Iceland’s dominant centre-right Independence Party recently joined a coalition led by the chair of the Left-Green Movement, Katrín Jakobsdóttir. In the election, the Left-Green Movement came second to the Independence Party, but Jakobsdóttir’s own popularity far outstripped that of her party, and the rest of the coalition. Sound familiar?

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Davey is also too pessimistic about what this unity government could achieve. It will need to sustain itself for long enough to properly address Brexit, which could take up to 12 months if another referendum were to produce a Remain result. Meanwhile, the government would need to address some of the other major crises facing this country.

Climate change has never been closer to the top of the political agenda. Parliaments and councils across the United Kingdom have been quick to respond and declare a “climate emergency”. Alexandria Ocasio-Cortez’s Green New Deal has made waves across the western world, empowered by Extinction Rebellion and other climate activists. Lucas is the perfect person to spearhead the first government with fighting climate change as a core priority.

Brexit has also highlighted the widening democratic deficit in this country, and therefore democratic reform must also be on the agenda so that the next parliament can regain the trust of the public.

Votes at 16, proportional representation, House of Lords reform, restoration of the Northern Ireland Assembly and further devolution will all need to be on the agenda. There could also be common ground on rolling back the devastating impact of austerity around the country.