How does it work?

Voters in 28 countries will elect 751 members of the European parliament for a five-year term that starts on 2 July. If Brexit goes ahead before then, British MEPs will not take up their seats.

When does it happen?

The election takes place this Thursday, 23 May, in the UK and in the Netherlands. Ireland and the Czech Republic go to the polls on Friday with Latvia, Malta and Slovakia on Saturday and the remainder of member states on Sunday.

How does the election work?

Postal vote ballot papers are already hitting doormats and the first thing you will notice is how long the ballot paper is and how different it is to that in the general election.

The ballot paper consists of lists of parties with a box containing a “closed list” of candidates pre-selected to run by the party. Independents are listed individually. The constituencies are multi-seat, ranging from three in the North East England constituency to 10 seats in South East England.

Can I chose in order of preference?

Only in Northern Ireland. Voters in England, Wales and Scotland can only place their cross beside one party.

The candidates running under an umbrella party are listed in the order of preference of the party and you cannot re-order that list.

What the ballot paper for the European Parliament election looks like in London. In the D’Hondt system Voters asked to chose a list of candidates pre-selected by a party. Only one X allows on the ballot paper (unlike Northern Ireland where STV applies). pic.twitter.com/zJCNZZgbzP — lisa o'carroll (@lisaocarroll) May 20, 2019

How does that work?

Parties put the candidate they rank as having the best chance of winning at the top of their list. For example, in London, the first two names to appear in the Labour party box are Claude Moraes and Seb Dance, two sitting MEPs, followed by six other party hopefuls in the eight-seat constituency.

Similar choices have been made by other parties. The Brexit party has placed Jacob Rees-Mogg’s sister Annunziata at the top of its list for the East Midlands while Change UK has put Stephen Dorrell, the former Conservative party health secretary, who defected to the new party this year, at the top of its list in the West Midlands.

The Green party has put incumbent Molly Scott Cato at the top of its list in South West England while the Liberal Democrats’ one existing MEP Catherine Bearder is top of the party’s list in South East England.

If a party gets one seat, the first candidate in their box is elected; if it gets two, the top two candidates on their list are elected and so on.

Anything else different?

Yes. There are only 12 constituencies in the UK for these elections compared with 650 constituencies for the general election.

The UK is divided into 12 electoral regions made up of the nations and regions of the UK.

The constituencies are:

East Midlands (five MEP seats)

East of England (seven)

London (eight)

North East (three)

North West (eight)

Northern Ireland (three)

Scotland (six)

South East (10)

South West (six)

Wales (four)

West Midlands (seven)

Yorkshire and the Humber (six)

The European election count in Southampton in May 2014. Photograph: Matthew Lloyd/Getty Images

How are the votes counted if I can only put my cross on one box?

In England, Scotland and Wales, the elections are run under a form of proportional representation, called the D’Hondt system. The single transferable vote system is used in Northern Ireland.

Under the D’Hondt system, the party with the most votes automatically wins a seat for the candidate at the top of their party’s list. Thereafter, the seats are allocated in a broadly proportional way.

In the second round, the leading party’s number of votes is divided and then the score sheet of all parties re-calibrated and so on until all seats are filled.

If an independent candidate got enough votes to get elected, the D’hondt process would continue with their number of votes divided by two (1+1 seat).

If they had so many votes, they qualified for a second seat in a subsequent round, the next candidate would be selected.

Does the UK have to use the D’Hondt system?

No. Member states must chose a proportional system, so first-past-the-post was never an option, but only 16 of the 27 countries use the D’Hondt system or variations of it.

And do they all use the closed list system?

Only seven used the “closed list” party system. Voters get to choose the order of candidates within the party in Finland, Sweden, Estonia, Latvia, Lithuania, Slovakia, Czech Republic, Austria, Slovenia, Croatia, Bulgaria, Greece, Cyprus, Luxembourg, Poland, Italy, Netherlands, Belgium and Denmark.

Illustrative example

Sample results, courtesy of the EU, for sample parties contesting five seats.

First round

Smartie party: 100 votes

Jelly Baby party: 80 votes

Lollipop party: 40 votes

Kit Kat party: 20 Votes

Aero party 10 votes

With the highest number of votes, the Smartie party wins the first MEP seat. It then has its original number of votes divided by one plus the number of MEP seats it has already won which equals 2. This means that, in the next round of counting, 50 of its votes are considered and it becomes the second party on the leaderboard leaving the Jelly Baby party with the most seats going into the next round.

Second round

Jelly Baby party: 80 votes

Smartie party: 50 votes

Lollipop party: 40 votes

Kit Kat party: 20 votes

Aero party: 10 votes

In this round, the Jelly Baby party is allocated a seat. Its 80 votes are now divided by two – the number of MEP seats plus one leaving it with 40 votes for the third round.

Third round

Smartie party 50 votes

Jelly Baby party: 40 votes

Lollipop party: 40 votes

Kit Kat party 20 votes

Aero party 10 votes

The third seat in this constituency goes to the Smartie party as it has most votes. Its original number of votes are now divided by three - the number of MEP seats (2) plus one – leaving it with 33 votes.

Fourth round

Jelly Baby party: 40 votes

Lollipop party: 40 votes

Smartie party: 33 votes

Kit Kat party: 20 votes

Aero party: 10 votes

The fourth and fifth seats go to the Jelly Baby and Lollipop parties in this constituency.

When will we know the results?

Not until 10pm on Sunday, as results cannot be announced before the last votes in Europe are made.

The results will start being announced from 10pm UK time with exit polls in some countries expected at abut the same time.