If the Government’s test and trace scheme worked seamlessly, a Covid-19 circuit-breaker would make a lot of sense.  A national lockdown would be imposed for a fortnight or so.  After which the hospitality sector could be re-opened; the rule of six dropped, and curbs on weddings, funerals, sporting and cultural events abandoned.

Voluntary action would take the strain of reducing the disease: hand-washing, masks, social distancing. All this could happen because testing, tracking and incarceration would operate to the required standard, with the 80 per cent target for those contacted being hit.

There would still be shutdowns, but they would take place on a much smaller scale – usually on a neighbourhood or even a street basis, because the state’s tracing capacity would be precise enough to enable such targeted action to take place.

But as ConservativeHome pointed out yesterday, the test and trace scheme is nowhere near having that kind of capacity.  If a small website can work this out, then so can the Government’s scientific advisers.  They know that for it to be effective, the circuit-breaker would have to be switched on for the duration, or at least lifted very slowly.

In other words, Keir Starmer has essentially come out for a full national lockdown of uncertain length.  Experience abroad suggests that this would not only bury the economy alive but fail to kill the virus, because the latter would still be lurking when the shutdown was lifted.  This would be the ultimate double whammy.

So a national circuit-breaker is a really bad idea.  In a policy sense, that’s all that needs to be said.  In a political one, it looks shaky, too.  This is both because the elecorate is a lot smarter than some people think, and will see through the Labour’s leader’s game, and because of opposition to the idea within his own party.

Four senior Labour local council leaders – from Liverpool, Manchester, Leeds and Newcastle – have declared themselves against more “economic lockdowns”.  Some local Labour MPs are bound to follow suit.  The Conservative Party is not alone in being divided on how to handle the virus.

Furthermore, striking out in his own direction, rather than swimming in the Government’s slip-stream, exposes Starmer to the risk of getting out of his depth.  The Conservatives will counter-attack, making some of the points that we do above, and adding a few more of their own.

Tory MPs are already busy on Twitter excoriating the Labour leader for backing a circuit-breaker, but not backing an element of one yesterday in the Commons – the ten o’clock rule; for giving his MPs a free vote while also instructing his party to abstain.

So given these downsides, why back a circuit-breaker?  Because Starmer takes a point that this site also made yesterday: that the Government is losing what control of the virus it has left.  He clearly believes that it is worth exposing himself to fire in order to move in for the kill, with polling support for shutdowns as cover.

For either Boris Johnson bows to the pressure for a circuit-breaker, in which case the Labour leader will claim the credit; or he won’t, and Starmer can pull the Prime Minister one way while Conservative rebels push him another – towards fewer lockdowns, not more, and a different strategy.

Forty-two of them voted against the Government yesterday evening on the ten o’clock rule – the biggest backbench revolt to date on a matter directly related to control of the virus.  There will be more where that came from as autumn turns into winter.

The Labour leader is settling down for a war of attrition in Parliament and elsewhere.  It is his boldest throw of the dice since he became Opposition leader, which makes him a more interesting figure – if also a grossly irresponsible one.