London CNN  — 

Boris Johnson has just imposed the most stringent social restrictions on the British public since the end of the Second World War.

With immediate effect, the UK is being instructed to stay at home, with exceptions for basic shopping, one form of exercise a day, medical need and some designated key workers. British police have been empowered to enforce the rules by dispersing gatherings and issuing fines.

The dramatic change comes after weeks of criticism that the PM has not taken the coronavirus outbreak seriously enough, while countries in Europe have moved faster and harder to contain it.

What’s taken Johnson so long? One hypothesis: He’s not naturally comfortable with removing anyone’s personal liberties.

Throughout his career, Johnson disparaged ideas of the “nanny state” and disdained the political instincts of those who use the state to tell the public what to do.

In a 2004 newspaper column, Johnson wrote of a proposed smoking ban: “We should have the common sense to listen to others before we presume to act in their interests.”

Mocking those who supported the ban, he wrote: “Next thing, I said, you’ll be wanting to ban drink in order to remove any temptation to get drunk, or ban cars, to avoid ever being tempted to drive too fast…”

His reluctance to tell others what to do goes beyond gags about drinks. In the same column, Johnson made reference to the Iraq war – and attacked the government of the time (now the opposition Labour party) who “decided, from a position of such ignorance, that the best way to help Iraq was to kill so many of its people.”

This stuff runs deep for Johnson. He has spent decades honing his image as a liberal Conservative who believes people should be free to live their lives how they wish. It is a seam which has run through his entire professional career: from editing magazines to running the official Brexit campaign.

The fact that Johnson has for years defined his political views as driven by personal liberty might go some way to explaining why the new rules are in fact a little less drastic than they initially sound.

Yes, movement will be limited – but even after this latest announcement, the UK’s response is still less strict than in Germany, France and Italy. Yes, the police can break up gatherings of people and impose fines – but there’s no mention of detention. And Johnson’s advisers were keen to remind journalists that the rules will be reviewed in three weeks,

The measures are nevertheless a big deal for the UK, as it slowly comes to terms with how serious this crisis really is. But Johnson will hope that the message towards the end of his address – “no Prime Minister wants to enact measures like this” – will reach the audience at home. And his team will be crossing their fingers that whenever these measures are lifted, it’s remembered that this was done with the heaviest of hearts.