ITV News Political Editor Robert Peston explains how the PM is being told by scientists reopening on June 21 will be 'too risky'
The prospect of the final easing of lockdown restrictions in England going ahead precisely as planned on 21 June are close to nil, according to ministers and officials. "It is clear some social distancing will have to be retained, not everything we've set out for 21 June is likely to happen," said a government adviser. "But it is also possible some of the easing we've done today will have to be reversed." Neither he nor a minister would be drawn on precisely which parts of the planned unlocking may have to be delayed, or which aspects of unlocking that's already happened would need rolling back.
They say it's dependent on data that will become available in around a fortnight, though the final decision is still around a month away.
These are the important factors (apart from the normal statistics on virus spread and incidence): 1) whether surge testing and accelerated vaccination of those more at risk succeeds in bearing down on the incidence of the Indian variant;
2) the magnitude of the Indian variant's increased transmissibility;
3) the magnitude of the reduction in the effectiveness of the AstraZeneca/Oxford vaccine on the Indian variant.
The health secretary said again on Monday that the evidence, from "viral neutralisation assays" taking place at Oxford, suggests the vaccines are effective against the Indian variant.
But it is important to note he did not say he is confident the AstraZeneca vaccine is as effective at reducing severe disease in those who catch the Indian variant.
I am told there are early signs that for the Indian variant the AZ vaccine may be between 10 and 15 percentage points less effective against severe disease. The efficacy of the Pfizer and Moderna vaccines is thought to be better.
To summarise: The AZ vaccine is still very much worth having, though it may work somewhat less well against the Indian variant.
Listen to our politics podcast, Calling Peston:
Apart from the Oxford study, there are also viral neutralisation assays being carried out by Wendy Barclay at Imperial College. And so-called real world efficacy is being studied by Public Health England and Prof Neil Ferguson. Separately, there is a scientific consensus the Indian variant is considerably more transmissible than the Kent one, though the figure of 50% increased transmissibility cited by ministers may turn out to be too high. The mathematical epidemiologist Erik Volz says that the outbreak in Bolton "may be an outlier", because of local social and cultural conditions. But if the vaccines were - for example - even 10% less effective and the virus was 30% more transmissible, that could still lead to a sizeable rise in hospitalisations. The ethical and political question for the prime minister would be whether to slow down or even reverse unlocking, if the disease were on the rise but there was no significant risk of the NHS being overwhelmed. Ministers tell me that is the big question pre-occupying Boris Johnson.
Listen to our coronavirus podcast