Coronavirus cases are down to less than a sixth of the January peak, according to data from the Office for National Statistics.
The ONS said infections were “likely level” in England and Northern Ireland in the week up to 3 April, but decreasing in Scotland and Wales.
Overall just under 0.3% of the population – one in 350 people – tested positive.
The R number for England is now estimated to be between 0.8-1.
On Friday, the UK reported the largest number of second vaccine doses in a single day at 449,269 – with 96,242 first doses also administered.
There were a further 3,150 confirmed cases in the past 24 hours, and another 60 deaths within 28 days of a positive test.
The government’s scientific advisers, Sage, said they were not producing a UK-wide estimate of R because of the “increasingly localised approaches” meant UK-level estimates “may not accurately reflect the current picture of the epidemic”.
The ONS suggests that in England, about one person in 340 tested positive in the week to 3 April.
In Northern Ireland, it was one in 300, in Scotland one in 410 and in Wales one in 800.
Across the UK as a whole, the study suggests that levels are similar to those seen in late September last year.
The REACT study, which also swabs people selected at random, suggested earlier this week that infections were levelling off, but suggested that the vaccination program is breaking the link between Covid-19 cases and deaths.
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