The UK is experiencing a marked increase in new Covid infections, say experts from the Office for National Statistics (ONS).
Latest data from swab tests in the community suggests one in every 160 people has the virus.
That is up from one in every 250 in the previous week. For England, it is the highest level since mid February.
The more infectious Delta variant now accounts for 99% of cases, according to Public Health England.
Around two-thirds of adults have now been double jabbed against the virus, and experts say this is helping prevent very big rises in Covid hospitalisations, although admissions are increasing.
Many of the infections being seen are among teenagers and young adults.
An estimated 400,000 people in the UK are thought to have been positive in the week to 3 July.
The final step of unlocking is expected to go ahead as planned on 19 July in England. It will be confirmed on 12 July after a review of data.
On Friday the latest government figures showed an increase of 35,707 Covid cases across the UK - the highest daily figure since 22 January. A further 29 deaths within 28 days of a positive test were also recorded.
Covid around the UK
According to the ONS Infection Survey findings for the week to July 3:
- In England, one in 160 people had the virus - up from one in 260 in the previous week and the highest level since the week to 19 February
- In Scotland, it was one in 100 people - up from one in 150 and the highest level since the week to 16 January
- For Wales, it was one in 340 people - up from one in 450 and the highest level since the week to 27 February
- In Northern Ireland it was one in 300 people - up from one in 670 and the highest since the week to 3 April
England's coronavirus R number has risen slightly to between 1.2 and 1.5, which means that, on average, every 10 people infected will infect between 12 and 15 other people.
Last week R was between 1.1 and 1.3.
Sarah Crofts from the ONS said: "We are seeing marked increases in infections across all four UK countries driven by the Delta variant, which continues to be the most common across the UK.
"As the vaccine rollout continues and restrictions are further lifted, it is crucial that we continue to closely monitor the data."
Dr Jenny Harries, chief executive of the UK Health Security Agency, said the sharp increase in cases being seen had not been followed by a similar increase in hospitalisation and death, suggesting the vaccines were working well.
"Two doses of the available vaccines offer a high level of protection against the Delta variant.
"Getting both jabs is the best way to ensure you and the people you love remain safe, so we once again urge everyone to come forward as soon as they are eligible.
"As we approach the planned end of restrictions, we must remain cautious and careful. Cases are rising across the country, and whilst the vaccines offer excellent protection, they do not offer 100% protection.
"Be sensible, and follow 'hands, face, space, fresh air' at all times and make sure to get tested if required."