I’ll vote “Yes” in the AV referendum on 5 May 2011, because I know it will be better for voters and the country than first past the post FPTP), but most politicians and many loyal party supporters (especially of small parties) will wonder how it will affect their parties.

Let’s admit at once that AV is unlikely to help small parties as much as proportional representation (PR), such as STV, would but that’s not the point. The comparison will not be between AV and any type of PR; it will be between AV and FPTP. AV is better than FPTP and should benefit small parties.

With FPTP, many Green and UKIP supporters often vote Labour to keep the Conservatives out or vice versa instead of voting for the candidate and party they really want to support. This makes it impossible to gauge the real level of support for UKIP and the Green Party and makes it hard for those parties to break through.

The same is true for one or other of the major parties in certain constituencies. For example, Labour probably has more potential supporters in Carshalton and Wallington than the 4,015 who voted Labour there this year, but the most of the rest probably voted Lib Dem to keep the Tories out and some may have voted Tory to keep the Lib Dems out. Interestingly, many Conservative and Lib Dem voters probably voted Green in Brighton Pavilion to keep Labour out. With AV, the Tory and Lib Dem support there would probably have been stronger, but Caroline Lucas would probably have still won for the Greens with transferred votes.

The essence of AV is that voters can express several choices instead of having to plump for one candidate as they do with FPTP for electing MPs.

This freedom of choice will allow Green and UKIP supporters to vote for their own parties first and for one of the larger parties second or later, so they can both support their own parties and avoid wasting their votes. This will reveal the true level of support for their parties and encourage more people to vote for them, thus increasing their chances of election.

Although in theory the BNP could do the same, they would be unlikely to achieve the same level of success as they have done in Council elections under FPTP, where they can win seats with only about 25% of the votes. This is because a candidate cannot win with fewer than half the valid votes with AV and supporters of mainstream parties will tend to give their second and third preferences etc to other mainstream parties rather than to the BNP. No wonder the BNP opposes AV! But it has some strange bedfellows - politicians who claim to be democrats.