You probably saw this a few days ago, but I suspect now is an important moment to reinforce the point: a YouGov poll was conducted on Thursday to test support for a lockdown in London, and found that people were overwhelmingly in favour.
At this time, would you support or oppose London being placed under a "lockdown" where people are not allowed to leave their homes except to go to work or get essential supplies?
There was strong support even among the subsample of London residents, ie. those who would be directly affected - 57% of Londoners were in favour, and only 27% were opposed. It's reasonable to assume that majority will just keep getting bigger as people wake up to the scale of the catastrophe that is unfolding.
Hopefully also the narrative has moved on since the poll was conducted, due to the disgraceful scenes all over the UK of people ignoring social distancing guidelines and acting like they're on a bank holiday break. Any lockdown self-evidently needs to be UK-wide. If there's any suggestion of it being confined to London, Nicola Sturgeon should insist (publicly if needs be) that it's expanded to cover Scotland.
The public demand a lockdown. The science favours a lockdown. (Needless to say I mean the international science associated with the WHO, not the discredited Blighty Knows Best "science" pushed by the herd immunity triumvirate of Cummings, Vallance and Whitty.) What remaining excuse has Boris Johnson got for not acting decisively to save hundreds of thousands of lives?