On 5 May the UK will go to the polls for our first nationwide referendum for 36 years. We are being asked whether we want to get rid of our current voting system (sometimes referred to as ‘First Past the Post’) and replace it with a different system called the ‘Alternative Vote’ (AV).

This referendum is being held because it was one of the things Nick Clegg and the Liberal Democrats demanded in return for their part in forming the coalition government. The Lib Dems will be campaigning for a ‘Yes’ vote in the referendum and a change to AV – while the Conservatives, along with over 100 Labour MPs, hundreds of Labour councillors, and a number of trade unions, are backing the cross-party campaign for a ‘No’ vote to keep our current system. Here are some of the reasons why:

• AV is unfair. For generations, our elections are based on the fundamental principle of ‘One Person, One Vote.’ AV would undermine that, allowing the supporters of fringe or extremist parties to have their vote counted five or six times – and potentially decide the outcome of the election – while people who backed the mainstream candidates only get one vote.

• AV is unwanted. Even the Yes campaigners don’t really want AV. Before the general election, Nick Clegg described AV as ‘a miserable little compromise’. Another senior Lib Dem, Chris Huhne, said that ‘it does not give voters real power’. Now they want it because it will help their party hold the balance of power.

• AV is obscure. Only three countries in the world use AV for their national elections: Fiji, Australia, and Papua New Guinea. Fiji have plans to get rid of it, and in Australia, 6 out of 10 voters want to return to the British system.

• AV is expensive. Holding this referendum is costing the country £90 million, and AV itself would make elections more expensive. Counting the votes would take much longer, either by hand or on costly new electronic counting machines – and local taxpayers would end up footing the bill.

As a case in point if last year’s general election had been held under AV, there would have been at least four rounds of counting before one candidate got over 50% of the vote in the Greenwich & Woolwich constituency.

That means the 65 voters who voted for the least popular candidate would have had at least 4 votes, and the 267 people who voted for the Trade Union and Socialist Coalition candidate would have had at least 3 votes.

But the 9 out of 10 mainstream voters who voted for the Labour, Conservative or Liberal Democrat candidates would have had their votes counted just once.

Please vote to defend our system of One Person, One vote, by voting ‘No’ on 5 May.

Alex Wilson is a councillor representing the Blackheath Westcombe ward and has been selected as the Conservative's London Assembly candidate for Greenwich and Lewisham.

My personal opinion on the ‘first past the post’ FPTP electoral system, which has traditionally determined British Parliamentary elections, is that it has two principal advantages. Firstly, it has generally delivered a clear winner, and so ensured a decisive outcome to elections. Secondly, it ensures there is always a direct link between Members of Parliament and a constituency.

By contrast, more proportional elective systems can create uncertain outcomes and they do bring the risk that small and often unrepresentative parties can gain disproportionate influence.

Another disadvantage of more proportional electoral systems is that they depend on large, multi-member constituencies, which makes it difficult for elected politicians to relate closely to a local area. For example, MEPs who are elected on a proportional system to represent us in the European Parliament have to represent the whole of London between them, so are inevitably less well-known to electors in a single area such as Greenwich and Woolwich.

Having said that, there are serious downsides to the FPTP system, notably that governments are usually elected with less than 50 per cent of the votes cast. For that reason, I am personally supportive of the Alternative Vote (AV) system for Parliamentary elections, which allows voters to place candidates in order of preference (1, 2, 3 etc.) rather than simply putting a cross besides one name.

Under the AV system, only candidates who secure more than 50 percent of the first preference votes are automatically elected. In other instances, the second preference votes of electors whose first preferences went to candidates who secured the least support are redistributed until one candidate reaches the 50 per cent threshold, or until all other candidates are eliminated. This gives greater weight to the views of those who voted for losing candidates, whilst retaining the link between MP and constituency. I will therefore be supporting the introduction of AV for British Parliamentary elections.

I have in the past helped introduce a similar system of voting. As Minister responsible for the Greater London Authority, I put in place the supplementary vote system for the election of the Mayor of London. This is very similar to AV but limits voters to just two preferences to guard against the risk of a candidate being elected as Mayor without having secured a substantial number of first preference votes. I believe that these arrangements have generally worked well.

The Alternative Vote Referendum will take place on May 5th 2011. Greenwich.co.uk will soon have an article putting the case for the No campaign.