Alternative vote referendum: What does it mean?

On 5 May the government has ordered a referendum on how we choose MPs.

At the moment it's the person who gets the most votes who wins, but that could all change with the alternative vote system.

What could the changes mean for you and what exactly is AV?

Why is there a vote on voting?

Some politicians and campaigners have wanted to change the way the UK chooses members of parliament for years. They claim the current system is unfair.

The Conservatives promised the Liberal Democrats that there would be a national vote on this single issue - a referendum - as part of the deal to form the coalition government last year.

All registered voters will be able to vote on 5 May. If you vote, this is the question you'll have to answer: "At present, the UK uses the 'first past the post' system to elect MPs to the House of Commons. Should the 'alternative vote' system be used instead?"

What system do we have now?

The current system is called First Past The Post. It involves a single cross in a box, next to the name of the candidate you want to win.

The candidate with the most votes is the winner, and like in a horse race, the winner - the first past the finishing post - takes all.

You could win by 1 vote or 1 million votes, but the margin of victory doesn't have any effect on the result. The winner is the one with the most votes. They don't need a clear majority. All the other candidates get nothing.

What is AV?

AV is the alternative vote system. You don't put a cross in the box next the candidate you want to win.

Instead you rank your favourite candidates, using 1,2,3 etc. The winner has to get at least 50 per cent of the votes, and that can include people who didn't put them first.

If no one gets 50 per cent when the votes are first counted, the lowest ranking candidate drops out and the 'alternative' votes that people put by their name go to the others.

The winner is the one who, in theory, has the broadest support.

How would it affect me?

If you are a voter you would have to do more than just a single cross in a box, but just a little more.

You'd probably have to pay more attention to the other candidates in the election as well because you'd be ranking them in order of preference, not simply picking one.

How would it affect the politicians?

In terms of election campaigns the politicians would probably have to do more to try to appeal to more people, because under AV they would be trying to get not just a single vote but 1st place, 2nd place, 3rd place votes.

Some voting experts who have looked at the figures say most MPs would not be affected at all.

One bit of research claims only 43 of 650 seats at the general election last year would have had a different result if AV had been used instead of First Past The Post.