Who would be her? At the Conservative party conference her party of lemmings strain at the leash to plunge over a Brexit precipice. She has little to lose by confronting them head on – and saving her country while she can. Here’s the speech Theresa May could make on Wednesday:

“There are times when prime ministers are called upon to make monumental decisions – on war and peace or on the economic future of our children and grandchildren. When the country faces a grave peril it falls to a leader to meet it without fear or favour to particular factions, ignoring threats to their personal survival. I am well used to this now.

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Stepping into No 10, I took on a country in a state of shock; a country so bitterly riven it seemed as if it might be beyond holding together. But I have tried my utmost. Now we have reached a political deadlock: within this party, in parliament and with EU negotiators.

It can be lonely when there is a clamour from all sides urging wildly different courses of action. This has gone beyond orthodox politics. Only a forensic examination of risks and opportunities can guide me now. You know I am not driven to hold on to this job at all costs. My intent is to take us through this so we emerge with the most hope and the least harm done. I will not go on and on – but I will go on until Brexit is fully resolved. That’s my duty.

Our history proves us the natural party of government, in power except when we grow complacent. Through our own folly, we now risk relinquishing power again. When Jeremy Corbyn claims to embody the new common sense, we should be laughing out loud.

Now it’s time to break the deadlock with a compromise that will be no one’s first choice. Call it everyone’s plan B

One strand of our party has led us astray. A kind of mania has distorted our pragmatic traditions, holding Brexit to be a miracle cure for every problem and only satisfied with an extreme form of departure from the EU.

The fantastical phrase-making of this group is more media-friendly than the sober political style of our chancellor or of myself. Jacob and Boris keep the country entertained – but this isn’t a reality show, it’s reality. Let’s face up to important truths, inconvenient for some. Compromise is the only way forward: you may not get your first choice, but everyone can unite to avoid their worst fear. I warn ardent leavers that by pressing for hard Brexit or no deal, they risk no Brexit at all. The mood of the country is changing. Prof John Curtice’s poll of polls shows support for remaining in the EU at 52%, an 8% swing, while the grim reaper replaces old leavers with young remain voters. The numbers are still close – but pause to reflect further before you claim your extreme Brexit is “the will of the people”.

To passionate remainers, I warn that if you block every deal, we may crash out with no deal, causing a seismic economic shock. Our best estimates suggest that “no deal” will cause an unthinkable 8% drop in GDP: it’s my duty to protect citizens from that fate.

After two years of Brexit uncertainty, the pound has dropped by 12%, with investment falling and the economy already 2.5% smaller than it would have been, leaving the Treasury £26bn less to spend. That’s a national loss of £500m a week. Boris, where is your £350m bus bonus for the NHS now?

“Preposterous” and “deranged” are not the kind of words I use. But your Canada model means long checks at every border, not just in Ireland. It will be the despair of industry. It will grievously damage the interests of farmers and manufacturers. Let us know when you invent your unicorn technology to wave all traffic through.

I tried to accommodate all sides. Perhaps I tried the impossible. Now it’s time to break the deadlock with a compromise that will be no one’s first choice, but which is gaining support. Call it everyone’s plan B, because it avoids everyone’s worst fears. Brexit must happen, but without harm. We will seek to stay in the European Economic Area (EEA) and the European Free Trade Association, asking for associate status, such as that once enjoyed by Finland. We will stay close to the single market, in the customs union, as Jersey is. Call it the Jersey plan. But we stay free of the EU common agriculture and fisheries policies.

EEA free-movement rules give us greater control over our borders. There would be no free movement of citizens, only free movement of workers: only those with a job can move here. This will address the concern that EU citizens come here to beg or to be a burden. Migrants with jobs bring prosperity.

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This EEA associate status would be temporary, a fixed three-year transition for negotiations. Our sovereign parliament always has power to change it. Our European neighbours will welcome frictionless borders for free-flowing trade, and no threat to the unity of the United Kingdom or of a hard border within the island of Ireland. Make no mistake, this is Brexit. No one knows which Brexit people voted for, but I do know most people want this done and dusted.

Offered this compromise deal, I trust enough of my MPs’ common sense to assert itself: to concentrate their minds, they should just glance over at the opposition. I believe MPs across the House will rally to this EEA associate option, regardless of their leaders’ positions. Every MP carries the same responsibility as I do for seeing the country through this.

But if MPs reject a deal, then the only option is to put this to the people and rely on their good sense.”

Could she? Would she? From all we know of her, Theresa May has no such agility or political imagination. History will record her as the worst of prime ministers if she drags the country down to a bad Brexit. But there is just time for her to rescue her legacy – and us – with a historic act of bravery.

• Polly Toynbee is a Guardian columnist