Whitty's words from the presser
It can be used to buy you time. Last winter the lockdown allowed the rollout of vaccines.
With more than 80% of the most vulnerable boosted the benefits of a lockdown are much lower this time.
The costs are the same, perhaps greater considering what people have endured so far in terms of the harm to jobs, mental health and education.
What would change the equation significantly is if the NHS is going to be overwhelmed, which would deny people basic life-saving care.
Clearly the NHS is struggling, doctors are pointing out care is suffering, but the situation is very different from last winter when over a third of beds were occupied by Covid patients.
Will that happen again? The modelling released so far is unclear as there is so much uncertainty.
Hospital cases could peak at half the level of last winter, or approaching double the level seen.