Another 12,872 people in Britain have tested positive for COVID-19, bringing the total number of coronavirus cases in the country to 480,017, according to official figures released Saturday.

The daily increase, which is nearly double Friday's 6,968 cases, is partly due to a technical issue which led to a delay in reporting data over the past week, according to a government statement.

The government said now that the technical issue has been fixed, the total reported numbers over the coming days will include some additional cases from the period between Sept. 24 and Oct. 1.

The coronavirus-related deaths rose by 49 to 42,317, the latest data showed.

The figures were revealed as tighter restrictions came into force at midnight on Saturday in parts of northern England after a sharp rise in coronavirus cases.

It is now illegal to meet people indoors from other households in the Liverpool City Region, Hartlepool, Middlesbrough and Warrington.

Health Secretary Matt Hancock said it was "necessary" to bring in the new measures and urged people in these areas to travel only when it is essential -- for example to school and work, and not to attend sports events as spectators.

The latest move came as Britain's R number, which shows the coronavirus reproduction, has risen to as high as 1.6, the latest official figures showed Friday.

The R number is now between 1.3 and 1.6, up from between 1.2 and 1.5 last week, according to the government's Scientific Advisory Group for Emergencies (SAGE).

If the reproduction rate is above one, it means the number of cases will increase exponentially.

More than a third of Britain's population is now under heightened restrictions, according to the BBC.

To bring life back to normal, countries such as Britain, China, Russia and the United States, are racing against time to develop coronavirus vaccines.

The British government's Chief Scientific Adviser Patrick Vallance has said that it is possible that some vaccine could be available in small amounts later this year, but it is more likely that a vaccine will be available early next year, although that is not guaranteed.