Voters in London and south-east England were seen wading through floodwater and were forced to brave torrential downpours to cast their ballots.
The capital is expected to see a month’s rainfall in the space of a few hours and a red Met Office weather warning is in place for parts of the country.
There were reports of flooded streets after overnight thunderstorms swept through, threatening disruption as voters head to polling stations.
Kingston upon Thames Council in south west London has moved two polling stations after they were inundated with water.
Polling stations in Devon Way in Chessington and Shiraz Mirza in New Malden have been relocated, while several others remain difficult to access because of the wet weather.
Out of 3,754 polling stations in the capital, five opened late because of the weather, a spokeswoman for London Councils said.
In Newham, east London, two stations opened slightly later due to issues with staff travel and flooding, and a station in Tower Hamlets, east London, and one in Redbridge, north-east London, were also affected.