“It was always right to pursue a local and a regional approach, as our scientific advisors said. And I’ll tell you why, Mr Speaker: because that approach, that regional approach, actually was showing signs of working and still is showing signs of working. It did get the R down, the transmission rate down, lower than it would otherwise have been, Mr Speaker”. 

That’s what Boris Johnson told MPs as he faced questions from Labour’s Keir Starmer about why the government didn’t impose a national lockdown in England earlier in the autumn.

But the Prime Minister’s claim about the advice he received is at odds with what the government’s Scientific Advisory Group for Emergencies (SAGE) told ministers in September.

And while the tiered restrictions may have reduced transmission compared to more relaxed measures, England’s Chief Medical Officer says that crucially, they did not push the R number below one.

What did the scientific advisors say?

Mr Johnson doesn’t say which scientific advisors he’s referring to, but SAGE has been key to the government’s strategy throughout the pandemic.

On 21 September, the committee examined a range of possible new restrictions that might be needed to control the virus.

They agreed: “The more rapidly interventions are put in place, and the more stringent they are, the faster the reduction in incidence and prevalence, and the greater the reduction in COVID-related deaths”. The experts said they had “high confidence” in this assertion.

As for the scope of the restrictions, SAGE agreed: “Both local and national measures are needed; measures should not be applied in too specific a geographical area”.

A paper endorsed at the same meeting proposes a “circuit-breaker” national lockdown and makes clear: “From a purely epidemiological position, implementing measures as soon as possible would have the largest effect and likelihood of bringing R back below one.”

The “R” refers to the rate at which people with the virus are passing it on to others. When it’s below one, the epidemic is shrinking – above that level, infections can quickly spiral out of control.

But instead of a circuit breaker, the government opted for a regional “Tier” system in England, which was announced on 12 October.

It wasn’t until 31 October that the government decided to introduce a temporary national lockdown in England, which took effect from 5 November and is slated to last a month.

Was the regional approach ‘showing signs of working’?

The Prime Minister says that the regional approach he announced in October “did get the R down, the transmission rate down, lower than it would otherwise have been”.

England’s Chief Medical Officer, Professor Chris Whitty, made similar comments to the Commons science and technology committee this week, telling MPs: “I am confident that the Tier 2 has had an effect and that the Tier 3 has had a bigger effect. […] I am confident that the rates are substantially lower than they would have been had those activities not happened”.

However, Mr Johnson omitted a key piece of context from his own remarks. According to Professor Whitty, “the early indications we have at present are that [the regional Tier system] has not achieved getting the R below one”. That’s an important test of the success or failure of a government intervention to control the virus.

Downing Street was contacted for comment.