England has reported a further eight Covid-19 deaths across hospitals, while Scotland has suffered the highest daily death toll in more than two months.
Three fatalities were recorded in Scotland in a single day for the first time since June 30.
No further deaths have been reported by Wales in the early count and Northern Ireland is yet to publish its figures.
Britain’s death toll will be officially announced by the Department of Health this afternoon and may be different to the preliminary total calculated by adding up deaths reported by each home nation.
New cases will also be reported later after almost 6,000 were diagnosed across Sunday and Monday – the highest since mid-May.
It comes as analysis of official data reveals those in their teens and 20s are making up the majority of new infections, more than tripling since July 4 – ‘Super Saturday’.
Cases in the over 85s are still declining from a peak in March and April, suggesting transmission has not yet spilled into the most vulnerable.
Nevertheless ministers are fearful hospitalisations will soon begin surging, as the Health Secretary Matt Hancock told MPs in the House of Commons today that ‘just because we’ve come through one peak, it does not mean we cannot see another one coming’.
NHS England reported eight deaths in English hospitals, all of which were between September 5 and September 7.
The figure reported by the Department of Health later may be smaller or larger than this because it has different cut-off times for counting deaths and it covers deaths outside of hospitals, too.
Scotland’s record high three Covid-19 deaths come after several weeks with barely any. It comes after Ms Sturgeon warned this week hospitalisations may also be on the up.
She revealed earlier that 176 positive cases of Covid-19 have been recorded in the last 24 hours in Scotland.
At the Scottish Government’s briefing in Edinburgh on Tuesday, she also said the ‘really unwelcome’ decision to impose strict rules was a ‘proportionate’ response to rising coronavirus cases.
There are now a number of mini-lockdowns around the UK to try and curb further spread of the coronavirus, the latest announced in the Welsh borough of Caerphilly.
The Welsh health minister has said local lockdown in the county borough of Caerphilly will not be lifted until October ‘at the very least’.
People will not be allowed to enter or leave the area without a reasonable excuse after the restrictions come into force at 6pm on Tuesday.
There have been a further 150 cases of Covid-19 in Wales, bringing the total number of confirmed cases in the country to 18,664.
Lockdown restrictions on household visits across western parts of Scotland have been continued for a further week – as well as being extended to other council areas.
Measures – originally introduced in Glasgow, East Renfrewshire and West Dunbartonshire – now also apply to East Dunbartonshire and Renfrewshire.
In England, various measures are in place across parts of Greater Manchester, East Lancashire, Preston, and West Yorkshire, Bolton, Pendle, Oldham, Leicester and Blackburn to try and keep cases down.
Bolton continues to have the highest infection rate in England, with 121.7 cases per 100,000, according to PA news agency.
West Midlands Mayor Andy Street said there had been ‘a very notable increase in Birmingham and Solihull’ infection rates in the last few days.
He said the imposition of ‘additional restrictions’ were now looking ‘likely’ while stressing no final decisions had yet been taken.
‘Everyone can see the numbers,’ added Mr Street.
‘That would be looking likely – and is in the context of a deteriorating national position, as well.’
In Birmingham, the infection rate in the week ending September 5 was 62.4 cases per 100,000 while in neighbouring Solihull it was 46.1, according to NHS Digital.