In parts of the UK coronavirus cases appear to be “plateauing”, says a government health advisor.

Chief medical adviser of the UK Health Security Agency, Dr Susan Hopkins, has said London, the South East and the East of England are all seeing the number of infections flatten.

Her comments came as other experts said they were optimistic about the coronavirus situation, while the Welsh Government began to ease restrictions.

Dr Hopkins told BBC Radio 4’s Today programme cases were still relatively high, with one in 15 people in England infected and one in 20 elsewhere in the UK, but that there was a “slow down” in hospital admissions.

She said: “We see that infections are plateauing in the community, which is good, in London and the South East and the East of England.

“There are still risings, but much slower in the northern parts of the country.

“All of that means we are seeing a slowdown in the number of admissions to hospital but they are slowing down rather than reversing at the moment, so there are still more than 2,000 admissions to hospital across the UK, and nearly 2,500 yesterday.”

She said that hospitals have been able to discharge patients faster due to Omicron being milder than previous variants. However, with around 15,500 people in hospital last week, she urged the NHS is still under “a lot of pressure”. Some trusts, she said, are “unable to do much of their elective care”. This is exacerbated by staff absences as many are isolating.

Prof Linda Bauld, a professor of public health at the University of Edinburgh and chief social policy adviser to the Scottish government, said Omicron cases in the UK appeared to be “stabilising”.

She told BBC Breakfast: “The cases, if we look at them, are going down by over 20%.

“In fact, yesterday I think was the last day, the first day for a while we’ve had less than 100,000 cases so things seem to be moving in the right direction.”

However, she cautioned the number of patients in hospitals was still “very high”.

She added: “I think we’ve got more data this week that suggests more optimism, and let’s hope, as we continue, that trajectory will be consistent and we can feel we’ve got through what’s been a really, really tough period.”

Dr Chris Smith, a consultant virologist and lecturer based at Cambridge University, said current coronavirus data gives him “great cause for optimism”.

He told BBC Breakfast: “The number of people who are going into intensive care or are on mechanical ventilation beds is actually dropping. It has remained flat.”

He added that, because of vaccines and reinfections, around 96% of the country now have antibodies against the coronavirus, meaning the vast majority of people can better “fend off” the disease.

Dr Smith said: “So we don’t see that strong connection of cases turning into consequences.”

Case numbers falling and a decline in the number of patients in critical care beds has meant Wales is to scale down from alert level two to zero over the coming weeks.

As a first step, the number of people who can be present at outdoor events in Wales has risen from 50 to 500 as of Saturday.