Poll clerks count ballots at the Kensington Town Hall during Britain's election in London June 9, 2017 REUTERS/Darren Staples

LONDON (Reuters) - Britain’s opposition Labour Party overturned a large majority to win the seat of Kensington in west London from Prime Minister Theresa May’s Conservatives on Friday, the final of 650 seats to declare its result.

Labour was declared the winner of the seat, where the Conservatives previously had a majority of more than 7,000, by just 20 votes, after several recounts.

It means the final tally of seats won by May’s Conservatives is 318, short of the 326 needed for a majority in parliament. Labour won a total of 262 seats.