The Government’s new tiered system of regional coronavirus controls for England will work – but only if people follow them, an expert has said.

Dr Julian Tang, an associate professor of respiratory sciences at the University of Leicester, said there is evidence the tier system was working before England went into lockdown.

He said: “It’s not that tiers don’t work, but if people don’t follow the tiers, then they won’t work.”

On December 2, shops, gyms and personal care services across England will be able to reopen in low-risk areas as lockdown restrictions are lifted.

I think people need a break, but if they have this break they have to be prepared for the consequences

But Prime Minister Boris Johnson also revealed that tightened Tier 2 measures will mean pubs, bars and restaurants will only serve alcohol alongside a substantial meal.

The decision has been met with dismay by hospitality bosses who said the Government’s latest pandemic tier system will “destroy the sector”.

But Dr Tang said while these restrictions will no doubt be tough on the hospitality industry and other businesses, they are necessary to slow down the transmission of coronavirus.

Dr Tang said: “When you have people meeting (in a pub or a restaurant), the fact that nobody gets a track and trace call-back to those people in the pub at that time does not mean transmission isn’t happening.

“It most probably does happen but they are just missed.

“A lot of these cases are very mild, especially in the 18-60 age group that go to the pubs, rather than the over-70s and 80s, and a lot of them will have asymptomatic infection.

“In fact, we know that asymptomatic infection rates could be as high as 10 to one or five to one.”

He said there is scientific evidence that places such as bars and restaurants can become Covid-19 hotspots, particularly if ventilation in the venues is poor.

A period of tiered measures in December is warranted now in order to allow some social mixing at Christmas

In these environments, simply talking to someone a short distance away poses a threat of viral transmission.

Dr Tang said exposure to the virus will be much more intense in indoor areas which have low ceilings – such as pubs, restaurants and school classrooms – where the air volume is more concentrated.

Meanwhile, he added, large venues with high ceilings – such as cinemas and auditoriums – are more likely to have “massive air dilution, so the virus will have more air to spread into and each person will take in less of the virus”.

Dr Tang, along with other experts, also said relaxing the rules for a few days during the festive period will see infections rise again.

He said the temporary relaxing of the restrictions would not be good from a virologist’s point of view, but added that it would give a much-needed “break”.

Dr Tang said: “I think people need a break, but if they have this break they have to be prepared for the consequences.”

Professor Liam Smeeth, a professor of clinical epidemiology and dean of the faculty of epidemiology and population health at the London School of Hygiene and Tropical Medicine, said: “A period of tiered measures in December is warranted now in order to allow some social mixing at Christmas.

“A further circuit-breaker in January, or possibly February, may well be needed because Christmas will place huge upward pressure on transmission rates.”