Keir Starmer tries to channel his inner Winston Churchill

Mild-mannered Keir Starmer is not cut out for Churchillian speeches that stir the blood. But the prime minister got as close as he ever will on Tuesday with the extraordinary announcement of a huge increase in defence spending to counter the threat from Russia’s Vladimir Putin.

To underline the gravity of the situation, Starmer staged a televised, live Downing Street press conference of the kind that normally marks a national emergency, such as a pandemic.

The threat he wanted to highlight on this occasion is rather more tangible than an invisible virus: that of military invasion.

He conjured up a chilling picture of enemy tanks rolling down the highways and byways of Britain, just like they have in Ukraine over the last three years.

It is not what Starmer expected to be doing when he won last year’s election.

There can be little doubt that two foreign leaders, not one, are responsible for the dramatic conversion of Starmer, hitherto one of life’s political doves, to being a hawk on defence.

Putin is one. The other is Donald Trump.

If Starmer was nervous about the kind of welcome that awaits him when he visits Washington for talks with unpredictable Trump on Thursday, his comments on Tuesday should help him relax.

Because, in effect, the prime minister is doing exactly what Trump told him – and the rest of Europe – to do: spending more on defending yourself, and saving the US billions of pounds.

Indeed, the White House wasted no time in congratulating Starmer for his actions.

However, the Oval Office may not be thrilled by everything the prime minister said.

Starmer went out of his way to pay tribute to “democratically elected” Volodymyr Zelensky – a clear riposte to Trump’s appalling slur that Ukraine’s president is a “dictator”.

And not everyone in Britain was impressed by Starmer’s performance.

Some of the harshest words were from his own Labour MPs, some of whom are horrified by the inevitable abandonment of overseas development projects to help the poorest – money that will now be spent on weapons and warships.

Moreover, Starmer’s detractors may say he is wasting his time trying to come over all Churchillian, that his military style has more in common with Captain Mainwaring from Dad’s Army.

To judge from Starmer’s demeanour at his press conference, he means what he says.

Time will tell whether it will be remembered as his finest hour.