Department of Health and Social Care data published on Friday showed that the daily growth rate of infections in the country was estimated to be between 3 per cent and 6 per cent, up from 0 per cent to 3 per cent in the previous week.
An R value between 1.2 and 1.4 means that, on average, every 10 people infected with the coronavirus will go on to infect between 12 and 14 other people.
The latest figures come amid growing concern over plans to lift Covid restrictions on 21 June, with cases rising sharply in parts of the UK due to the arrival of the Delta variant (previously known as the Indian variant).
Public Health England (PHE) warned on Friday that data suggested cases of the Delta variant were estimated to be doubling every four and a half days in parts of England.
The agency said that 42,323 cases of the variant had been confirmed in the UK, as of Friday, up by 29,892 from last week.
PHE also said that more than 90 per cent of new Covid-19 cases were now the Delta variant, with new research suggesting it was associated with an approximately 60 per cent increased risk of household transmission compared with the previously dominant Alpha variant.
Boris Johnson is expected to announce next week whether the next stage of the government’s roadmap out of lockdown will go ahead, with talk of a possible delay of at least two weeks to the lifting of restrictions.
Meanwhile, data from the Office for National Statistics showed on Friday that the percentage of people testing positive for Covid-19 was estimated to have increased in north-west England, the West Midlands, London and south-east England.
The figures, covering the week to 5 June, also suggested that there were early signs of a decrease in eastern England, while the trend was uncertain for other regions.
As Covid positivity rates are very low in many regions, it is currently difficult to identify trends because there are only small changes in the number of people testing positive from week to week.
Additional reporting by PA