The UK has recorded a further 174 COVID deaths – the highest daily figure since 12 March.
30,838 new coronavirus cases have also been reported in the latest 24-hour period.
This time last week, 17 August, the UK recorded 26,852 cases and 170 deaths.
It is the highest number of daily deaths since 175 were recorded on March 12.
On Monday, 46,401 people were given their first dose of a vaccine, taking the total number to 47,737,142 – 87.8% of the UK’s population aged over 16.
131,283 people were given their second dose, which means 77.2% of the population is now fully inoculated.
It comes as weekly coronavirus-related deaths in the UK have reached their highest level since March, the Office for National Statistics said.
There were 652 COVID deaths registered in the week ending 13 August, an increase of 6.7% on the previous week.
Around one in 18 deaths registered (5.5%) mentioned COVID-19 on the death certificate.
It is the highest number since 800 fatalities involving COVID were registered in the week ending 26 March.
The ONS said the latest total includes 550 deaths in England, 41 in Scotland, 40 in Northern Ireland and 19 in Wales.
Scotland’s First Minister Nicola Sturgeon has said she cannot rule out re-imposing some COVID restrictions, following a “substantial increase” in cases.
She told a Scottish government coronavirus briefing that new cases had almost doubled in the past week, and said the country had reached a “fragile and pivotal moment in our journey through the pandemic”.
Scotland has also announced plans to establish a judge-led public enquiry into its government’s handling of the health crisis.
People infected with the more transmissible Delta variant have a viral load 300 times higher than those with the original version of COVID-19, researchers in South Korea have found.
This means the virus spreads more easily from person to person, increasing infections and hospitalisations.
“But it doesn’t mean Delta is 300 times more infectious… we think its transmission rate is 1.6 times the Alpha variant, and about two times the original version of the virus,” said South Korean health ministry official Lee Sang-won.
The Delta variant was first identified in India and the Alpha variant in the UK.
Almost 5,000 coronavirus cases in the UK are suspected to be linked to a surf and music festival in Cornwall, with health officials launching an investigation.
4,700 people have tested positive following Boardmasters in Newquay earlier this month – 800 are thought to be living in Cornwall, but cases are spread across the UK.
It comes despite festival-goers aged 11 and above being asked to demonstrate their COVID status via the NHS app before being allowed to enter the sold-out event.
Attendees had to prove they were either double vaccinated, show a negative lateral flow test taken within 24 hours of arriving, or that they had natural immunity following a positive PCR test taken at least ten days earlier.
Cornwall and the Isles of Scilly recorded the second-highest rate of coronavirus cases out of 312 areas in England, up from 383.5 per 100,000 to 717.4 – with 4,129 new cases in the week up to 19 August.
Mayor of Newquay, Louis Gardner – who owns a deli in the town – said: “We’re seeing a spike in Cornwall because we’ve got the highest number of visitors we’ve ever had.”