Explainer: What happens in UK parliamentary election?

Britain will hold a parliamentary election on July 4 which opinion polls indicate will hand power to Keir Starmer's Labour Party and end 14 years of Conservative Party-led government.

How is the winner decided?

To win outright, one party needs to win at least 326 out of the 650 parliamentary seats. The leader of that party becomes prime minister.

In each of the 650 constituencies, voters elect a local candidate who is usually affiliated with a larger political party. Voters choose one candidate and the candidate with the most votes wins the seat.

A hung parliament occurs if no single party wins a majority. In this case the incumbent prime minister remains in power and is given the first chance to form a government either by building a coalition or governing with a minority.

What is a supermajority?

During the Conservative Party's campaign, it warned that Labour could win a 'supermajority' that would embolden it to make more radical reforms than those set out in its manifesto.

In some democracies, a supermajority is a legally defined threshold, higher than a simple majority, required to make major changes such as to a constitution.

In Britain, however, there is no definition of a supermajority that gives governments any special powers and the term has no clear meaning in its political lexicon.

When will the results be announced?

An exit poll is released by broadcasters immediately after voting ends at 10 p.m. (2100 GMT).

Vote counting begins immediately and first results come within hours. Most are declared overnight and the outcome is usually clear between 5 a.m. and 7 a.m.

When will the new prime minister take office?

Once the overall result is clear, and if the governing party has lost, the prime minister would be expected to tender his resignation to the king on Friday.

The leader of the winning party will then meet the king, who will request he or she form a government. They will then head to Downing Street to make a speech to the British public as the new prime minister.

What happens once a new prime minister is in place?

The new prime minister will begin appointing ministers, starting with senior positions.

Parliament is scheduled to return on July 9. The Speaker of the House of Commons - parliament's lower chamber - will be elected from among members of parliament (MPs).

Each MP will then in turn swear the oath of allegiance to the king or make a solemn affirmation. This usually takes a few days.

The State Opening of Parliament and King's Speech, setting out a government's programme of legislation for the parliamentary session, is due to take place on July 17, although this date could be changed by a new government.

Who can vote and how?

Voters must be aged 18 or over on polling day, and be either a British citizen, Irish citizen or qualifying Commonwealth citizen.

Close to 50 million people are registered to vote. Polling stations open from 7am to 10pm (0600-2100 GMT). Votes can be cast in person, by post, or through a proxy.

Voters must take photo I.D. with them to vote, the first national election at which that has been required.

Overseas British citizens will also get to vote regardless of how long they have been living outside the country.