The Conservatives had a thumping majority in 1940.  Yes, on paper the Government was a National Government.  But it was in practice a Tory-dominated one, with the Conservatives having won 387 of the Government’s 429 seats in 1935.

None the less, the exigencies of war compelled a wartime coalition government, including Labour, headed by Winston Churchill.

The Liberals were in a good position in 1915 – in terms of Commons numbers, at any rate.  The second general election of 1910 had left them with only one more seat than the Conservatives.  But they were propped up in power by 70 or so Irish Nationalist MPs.

However, war had weakened H.H.Asquith’s administration, and he was compelled to turn to the Conservatives to form a wartime coalition.

Readers will see where all this is going.

Boris Johnson has a near-landslide majority of 80.  Unlike Chamberlain in 1940 or Asquith in 1915, he has not held office for long and nor is his administration exhausted.  Indeed, he won his near-landslide election victory only just over three months ago.

But is it impossible to imagine, presumably after Keir Starmer (presumably) becomes Labour leader on April 4, that the Prime Minister will feel he must form some sort of all-party “War Cabinet” – and a national administration?

At present, co-operation between the two main parties is holding after a wobble last weekend.  Labour front-benchers are being briefed on privy council terms.  Cabinet members are consulting their shadow counterparts.  The local elections have been cancelled – and the party political temperature thereby cooled.

If the death toll soars relentlessly; if NHS pressures becomes unbearable; if mass social distancing is not observed, and if there are problems with essential supplies and public order – that’s four big ifs – is a next step unimaginable?

One can conceive of Ministers seeking an all-party public front, and Labour objecting to responsibility with no power.

Those wartime brief histories are in one sense not precedents.  Britain is not at war.  But the struggle against the Coronavirus is in some ways like one – which is why so many are now using the metaphor.  Indeed, the damage that it threatens to wreak on the economy, here and abroad, could in some respects be even more severe.

To fall back on a figure of speech we’ve used before, the impact of the virus may be comparable to a mass attack of V2 rockets, taking out major sectors of the economy in our major cities and towns.

From a Tory party political vantage, the argument potentially cuts either way.

On the one hand, it looks like an elementary strategic error to help make Labour electorally respectable by allowing its leaders the respectability of office.

On the other, if Ministers must take increasingly controversial decisions, it might be wise for the fingerprints of the Labour Party also to be on the steering wheel.

And looming above both vantages is the national interest.

“If the crisis becomes existential, then it’s imaginable,” one Cabinet member told ConHome.  “But I haven’t heard any talk of it and, after December’s results, we are the national party – representing all parts of the country.”

“After the events of recent years, you can’t rule anything out,” said another, looking back to the EU referendum, the resignation of David Cameron, Theresa May’s leadership victory, the 2017 general election reverse, Parliamentary gridlock, over 40 Ministerial resignations, Change UK, May’s fall, Johnson’s arrival, the Supreme Court ruling…and last December’s election.

It is almost impossible to imagine Jeremy Corbyn and John McDonnell, with Len McLuskey and Seumas Milne in the wings, sharing space round the Cabinet table with Johnson and Rishi Sunak.  (Though remember: May fell back on pleading with them to get her deal through – one of the main causes of her downfall.)

A Starmer-led Opposition with the likes of Yvette Cooper, Rachel Reeves and Hillary Benn back on board might be different.  We raise the prospect not to recommend it, but to say: you read it here first.