COVID-19 pandemic
Mark Sedwill also says there are "legitimate" questions over UK's preparedness for the coronavirus pandemic.
Exclusive: Campaigners say ministers have done nothing to stop a repeat of the first wave, which saw Black and Asian people disproportionately hit.
Donald Trump’s daughter said her father had taken “unprecedented” actions to tackle the coronavirus pandemic when others were “not taking it seriously."
Different parts of England will be split into "medium”, “high” or “very high” local Covid alert areas under the new system of restrictions.
Boris Johnson is set to outline a new three-tiered system of restrictions from Monday.
The British Medical Association (BMA) said clearer, stronger measures are needed to control spiralling number of Covid-19 cases.
Northwick Park in north-west London was the first UK hospital to be overwhelmed by coronavirus in March. Here's what's different this time around.
With uncertainty comes a need to think positively and with agility, writes James Melville.
Whitehall has been urged to take stronger action as infections increase dramatically, with 17,540 lab-confirmed cases reported on Thursday.
But Commons authorities have refused to reveal how many new cases have been recorded in recent days.