London, Jun 5 (IANS): The UK has reported the highest single-day coronavirus case surge in more than two months, according to official figures.

The new 6,238 coronavirus cases on Friday increased the country's overall infection tally to 4,521,919, the seventh highest in the world, Xinhua news agency reported.

The death toll spiked to 128,086 after 11 more people succumbed to the disease.

Meanwhile, England's coronavirus reproduction number, also known as the R number, has risen slightly to between one and 1.2. Last week, the figure stood at between one and 1.1.

The latest R number indicates that on average every 10 people infected will infect between 10 and 12 others.

When the figure is above one, an outbreak can grow exponentially.

The latest data came as Public Health England (PHE) said the B.1.6172 coronavirus variant, also known as Delta, is now the "dominant" strain in the UK.

The number of cases of the Delta variant has risen by more than 5,000 since last week to 12,431.

PHE officials said that the Delta variant has now overtaken the Kent variant, known as Alpha, as the most dominant.

There is "early evidence to suggest there may be increased risk of hospitalisation" from Delta, but further data is needed to confirm this, according to the PHE.

Meanwhile, Health Secretary Matt Hancock confirmed that more than three-quarters of adults in Britain have now had their first Covid vaccine dose.

Nearly 40 million people, or three-quarters of adults in Britain, have been given the first jab of the coronavirus vaccine, according to the latest official figures.

The British government is facing increasing pressure to delay the final step of unlocking restrictions in England on June 21 due to concerns over the spread of the Delta variant.