British Prime Minister Boris Johnson is set to present a new three-tiered alert system for coronavirus cases in England on Monday, with northwestern Liverpool expected to be the only city placed in the top category.

Like governments throughout Europe, Johnson's conservative cabinet is seeking to balance bringing down the rate of new infections against concern about the economy and frustration among voters. The new alert system, which will classify all areas as either "medium", "high" or "very high" risk, is an attempt to bring transparency and uniformity to restrictions introduced to combat the spread of the disease.

The BBC reported that Liverpool would be the only city placed in the top category, meaning its pubs and restaurants would have to close -- against the wishes of local authorities. "This is a critical juncture and it is absolutely vital that everyone follows the clear guidance we have set out to help contain the virus," said a Downing Street spokesperson.

British finance minister Rishi Sunak announced on Friday said he would pay up to two-thirds of staff monthly wages to firms forced to close over the winter months under the new system's highest level of lockdown.

Mayors representing several northern English cities, including Manchester and Liverpool, have said the new support falls short for those on minimum wages like bar staff and kitchen workers, and self-employed people such as taxi drivers and security guards.

Several urban centres in northern England have already been hit with a range of curbs on social life such as a ban on different households mixing, but the south has escaped stricter restrictions for now. Scotland, Wales and Northern Ireland have their own devolved governments and separate health systems. Pubs across central Scotland have closed for just over two weeks to try to cut close-contact transmission.

Johnson is set to present the system in parliament on Monday afternoon and MPs will be called to vote on the measures later in the week, a source in his office said. The national death toll from coronavirus in Britain is more than 42,000, which is the worst in Europe.

On Sunday, 12,872 people in Britain were reported to have tested positive for coronavirus.