The news about the Pfizer vaccine has persuaded Tory MPs that there is now a route out of this crisis, and that this country can avoid being dragged into a cycle of lockdowns, I say in the magazine this week.

No. 10 is being deliberately cautious about the vaccine. There are huge logistical obstacles to overcome before the vaccine can be rolled out. It needs to win approval from the regulators (although if it passes the safety test, that should happen quickly). It must also be kept colder than the North Pole until it is sent out to be delivered to patients.

But in Whitehall the view is that Pfizer’s vaccine breakthrough will be followed by others, because the apparent success shows that a mRNA vaccine (rather than one using a weakened or dead form of the virus) can work. I’m told there are ‘really encouraging signs from pretty much the whole pipeline’ of vaccines. Indeed, Antony Fauci, the head of the US’s National Institute of Allergy and Infectious Diseases, told Chatham House today that another vaccine candidate will soon announce good data.

If all goes well, and more than one vaccine is available, the UK will be able to move quickly from vaccinating the most vulnerable to seeking to immunise nearly all adults. But at the moment, the government is talking about only vaccinating half the population.

The growing desire in Whitehall to immunise a significant majority of the population is being driven not just by the imperative of returning the economy to normal as quickly as possible, but by mounting concerns inside government about ‘long Covid’ and how it can affect young people who catch the virus. The question now becomes whether the government can run a rapid, and successful, immunisation campaign of unprecedented scale.