The British government faced pressure Tuesday to act fast to keep a lid on coronavirus infections after a sharp spike in new cases across the U.K. over recent days stoked concerns about the pandemic's prospective path during winter.

In the wake of figures Monday showing that the U.K. recorded nearly 3,000 new coronavirus cases for the second day running, there is mounting speculation that the British government is considering tightening some restrictions, such as reducing the number of people who can gather indoors in England from the current limit of 30.

Talk of new lockdown restrictions comes as government ministers and scientists have voiced concerns that the easing of the lockdown during the summer has prompted many people, particularly young adults, to let their guard down in a country that has seen Europe's deadliest virus outbreak.

``This is a big change, it's now consistent over two days and it's of great concern at this point,'' said Professor Jonathan Van-Tam, the government's deputy chief medical officer.

``We've been able to relax a bit over the summer, the disease levels have been really quite low in the U.K. through the summer but these latest figures really show us that much as people might like to say `oh well it's gone away' _ this hasn't gone away.``

While noting that the rise is ``much more marked'' among young people between the ages of 17 and 21, he said there is a ``more general and creeping geographic trend'' across the U.K.

``People have relaxed too much,'' he said. ``Now is the time for us to re-engage and realise that this is a continuing threat to us.''

The U.K. has Europe's worst death toll from the virus, recording more than 41,500 deaths within 28 days of testing positive. The actual toll is believed to be far higher as the government tally does not include those who died without having been tested.

The spike in U.K. cases follows big increases in Spain and France, both of whom have seen the number of COVID-19 patients being hospitalized rising dramatically during the summer.

The worry is that the U.K. will start seeing a big increase in the number of people being hospitalized _ and dying _ over coming weeks, given lag effects.

``Although we are encouraged to return to the workplace to support jobs, cafes and so on, we need to do so responsibly,`` Communities Secretary Robert Jenrick told Sky News.

``As we approach the autumn and winter there is going to be even more responsibility on all of us to keep following the guidelines.``

The government has faced criticism for its mixed messages since it started easing the lockdown, which was introduced in March. It spent much of the summer, for example, encouraging people to go out to help the hard-pressed hospitality sector, notably through an August eating-out discount scheme. Following the reopening of schools, it is now making the case that workers should return to their offices.

Professor John Edmunds, an epidemiologist at the London School of Hygiene & Tropical Medicine, said it's clear cases are rising though not spectacularly, but he worried about what will happen in coming weeks following the reopening of schools and universities.

``There are big movements afoot in the country and these will inevitably accelerate transmission,'' he told Sky News. ''I'm not sure we have to go back to work when we can work from home.``

Another criticism of the government centers around testing for the virus, amid mounting reports that people aren't able to get a test at the time and place of their choosing and a lack of home kits that can be mailed.

Sarah-Jane Marsh, director for the National Health Service's Test and Trace program, apologized to people unable to get a test and said that issues with laboratories is behind the current problems.

``All of our testing sites have capacity, which is why they don't look overcrowded. It's our laboratory processing that is the critical pinch point,'' she said. ``We are doing all we can to expand quickly.''

She said new lab capacity is due to open up ``imminently'' and that the agency is expanding its use of tests outside of labs.

``The testing team work on this 18 hours a day, seven days a week,`` she said. ``We recognize the country is depending on us.''

Despite the recent issues, the U.K. is testing tens of thousands more people than it did in the early months of the pandemic. On Monday, it processed around 175,000 tests.

Although the higher cases can partly be attributed to more testing, it's clear there's been an uptick in the past few weeks _ daily infections are about double the level they were the previous week. In some places, local outbreaks in Britain have been so severe that many lockdown restrictions have been reimposed.

Later Tuesday, a local lockdown comes into force in the Welsh district of Caerphilly following a spike in cases. Under the new restrictions, people will not be allowed to enter or leave the area without a reasonable excuse. Everyone over the age of 11 will also be required to wear face coverings in shops _ the first time this will be mandatory in Wales. Meetings with other people indoors and extended households will not be allowed, while overnight stays have also been banned.