The UK's coronavirus alert level has been reduced - as two rare types of Omicron have been reclassified as variants of concern.
The level has moved from four to three after advice from the four nations' chief medical officers and the NHS England medical director.
Their statement added: "Whilst it is reasonable to expect the number of cases to increase due to BA.4, BA.5 or BA2.12.1, it is unlikely in the immediate future to lead to significant direct COVID pressures."
The alert level was last raised on 12 December as Omicron spread rapidly.
Read more: The UK's COVID alert level explained
UK coronavirus infections are now believed to be at their lowest for five months - and a quarter of what they were in March.
They have fallen again - from an estimated 1.5 million last week to 1.3 million, according to the latest Office for National Statistics (ONS) survey.
Around one in 55 people had the virus in private households in England in the week to 13 May, the ONS said.
Last week, it was one in 45.
Wales' infections fell from an estimated one in 35 to one in 40; Scotland's from one in 35 to one in 45; and in Northern Ireland it's down from one in 55 to one in 60.
New Omicron types may have 'immune escape'
Despite significant and consistent falls, two new sub-lineages of Omicron - BA.4 and BA.5 - have been reclassified as variants of concern by the UK Health Security Agency (UKHSA).
It said they are likely to have a growth advantage over the dominant BA.2 type.
Initial findings also suggest they may also have some degree of "immune escape", meaning the body may no longer be able to recognise or fight the virus.
However, there's so far no indication they are associated with new symptoms or more severe disease, according to vaccine alliance GAVI.
Only 115 probable or confirmed BA.4 cases have been identified in the UK as of 20 May.
There are 67 in England, 41 in Scotland, six in Wales and one in Northern Ireland.
Some 80 cases of BA.5 have been identified, including 48 in England, 25 in Scotland, six in Northern Ireland and one in Wales.
Dr Meera Chand, from the UKHSA, said: "The reclassification of these variants as variants of concern reflects emerging evidence on the growth of BA.4 and BA.5 internationally and in the UK.
"Whilst the impact of these variants is uncertain, the variant classification system aims to identify potential risk as early as possible.
"UKHSA is undertaking further detailed studies. Data and analysis will be released in due course through our regular surveillance reporting."
BA.4 and BA.5 were first detected in South Africa in January and February respectively, according to GAVI.
It said that the number of countries reporting cases, as well as overall cases, were rising.
"This growth could suggest that these variants are more transmissible than the existing Omicron variant, or it could the result of waning immunity from past infection or vaccination - it is too early to know for sure," it said.
The reclassification of BA.4 and BA.5 as variants of concern comes after UK experts recommended an autumn COVID booster jab for some people.
Over-65s, care home residents and staff, frontline health and social care workers, and people over 16 in vulnerable groups should be offered another vaccine to boost immunity ahead of the winter, said the Joint Committee on Vaccination and Immunisation (JCVI).