British Prime Minister Theresa May's decision to call an early election in a bid to strengthen her grip on power appeared to have spectacularly backfired, with her Conservative Party at risk of losing its parliamentary majority, according to exit poll and partial official results.

A projection based on a combination of exit poll and official results put the Conservatives at 322 seats - four short of what they would need for a working majority in the 650 member Parliament and down from 331 they had won just two years ago.

"The prime minister called this election because she wanted a mandate," said Corbyn in a speech after winning reelection to his north London seat. "The mandate she's got is lost votes, lost Conservatives seats, lost confidence."

"Could be messy for the United Kingdom in the years ahead," tweeted former Swedish prime minister Carl Bildt. "One mess risks following another. Price to be paid for lack of true leadership."

"If I lose just six seats I will lose this election, and Jeremy Corbyn will be sitting down to negotiate with the presidents, prime ministers and chancellors of Europe," she wrote on her Facebook page last month.

"We've learned what we suspected all along: She's not particularly fast on her feet, she's not a natural campaigner, she's not really a people person," said Tim Bale, a politics professor at Queen Mary University of London.

By Premji