Prime Minister Boris Johnson has warned it is “absolutely crucial” to follow lockdown rules as research shows a 50% increase in the prevalence of coronavirus in England.

Mr Johnson said research, including the React study from Imperial College London, showed that current levels of coronavirus were still too high.

When questioned whether the lockdown may not be eased until the summer, he told reporters: “I think it’s too early to say when we’ll be able to lift some of the restrictions.

“We’ll look then (February 15) at how we’re doing but I think what we’re seeing in the ONS (Office for National Statistics) data, in the React survey, we’re seeing the contagiousness of the new variant that we saw arrive just before Christmas – there’s no doubt it does spread very fast indeed.

“It’s not more deadly but it is much more contagious, and the numbers are very great.”

The study shows a 50% increase in coronavirus infection rates across England between early December and the second week of January.

143,000 volunteers were tested in England between January 6 and 15, with results showing that one in 63 people were infected.

Salford City News: Daily confirmed cases of Covid-19 in the UK (PA)Daily confirmed cases of Covid-19 in the UK (PA)

The researchers said their findings showed there were “worrying suggestions of a recent uptick in infections”, covering part of the period of the latest lockdown.

National prevalence of the virus increased by half, from 0.91% in early December to 1.58%, the study found.

While there was a rise in prevalence across all adult age groups, it was highest in 18 to 24-year-olds, and more than doubled in the over-65s age group.

London saw the highest regional prevalence, jumping from 1.21% to 2.8%, while there were also rises in the South East, East of England, West Midlands, South West and North West.

The only region to see a decrease was Yorkshire and the Humber, and prevalence remained stable in the East Midlands and North East, but the researchers warned infection numbers were still high even in these areas.

Professor Paul Elliott, director of the programme at Imperial, warned that if prevalence continued to be so high “more and more lives will be lost”.

He said: “Our data are showing worrying suggestions of a recent uptick in infections which we will continue to monitor closely.

“To prevent our already stretched health system from becoming overwhelmed, infections must be brought down; if prevalence continues at the high rate we are seeing then hospitals will continue to be put under immense pressure, and more and more lives will be lost.

“We all have a part to play in preventing this situation from worsening and must do our best to stay at home wherever possible.”