Millions of British voters began casting their ballots as polling stations opened for local government elections on Thursday.

Votes will decide almost 7,000 council seats across the United Kingdom, determining the makeup of 140 local government authorities, which are responsible for the day-to-day provision of public services.

The elections are seen as a test of support for Prime Minister Boris Johnson, who became the first British leader in living memory to have broken the law while in office when he was fined last month for attending a birthday gathering in his office in 2020 when COVID-19 lockdown rules were in place.

A poor set of results will increase pressure on Johnson, who faces three investigations and the possibility of more police fines over his attendance at other lockdown-breaking gatherings.

On Thursday morning Johnson, accompanied by his dog Dilyn, went to a polling station at Methodist Central Hall a short walk from his Downing Street residence to cast his vote.

The results will not directly affect Johnson's practical ability to govern because the vote does not cause seats in parliament to change hands.

But with the main opposition Labour Party trying to press its criticism of the government's response to a cost-of-living crisis, a poor performance could embolden critics in his party who wonder if he is still an electoral asset ahead of the next general election that must be held before the end of 2024.

Two of the key results in London will be Wandsworth and Westminster, both traditionally Conservative strongholds that now could be within reach of Labour.

The stations will close at 10:00 p.m. local time, with results expected to start coming in from the early hours of Friday.

(With input from Reuters)

(Cover: British Prime Minister Boris Johnson arrives to vote at a polling station during the local elections in London, Britain, May 5, 2022. /Reuters)