An estimated 5.3 million booster doses of Covid-19 vaccine have been delivered in the UK, new figures show.
It is the first time data on boosters has been reported by all four nations.
A total of 4,524,517 doses have been delivered in England, along with 429,801 in Scotland, 322,591 in Wales and 43,536 in Northern Ireland.
It means around one in nine people in the UK who have received a first and second dose of vaccine are likely to have also received a booster.
The figures have been published by NHS England, Public Health Scotland, Public Health Wales and the Northern Ireland Department of Health.
The total for England includes a small number of third primary doses of vaccine, NHS England said.
Wales currently leads the other nations in the proportion of double-jabbed people who have also received a booster, at 14.4%, according to analysis by the PA news agency.
The equivalent proportion for England is 11.9%, with 11.1% for Scotland and 3.5% for Northern Ireland.
A breakdown by age group suggests more than half of double-jabbed people aged 80 and over in England have now had a booster (53.6%), compared with just under a half (47.2%) in Wales.
Some 39.8% of eligible 75 to 79-year-olds in England have also had a booster, along with 30.6% in Wales.
Data on booster take-up among age groups in Scotland and Northern Ireland is not yet available.Internet Explorer Channel Network