Supporters of FPTP often promote tactical voting as a way minority party supporters can make their vote count.
While tactical voting under FPTP can obviously give a minority party supporter a greater influence over the outcome of a FPTP election, it is at a huge cost to the voters real desire.
With tactical voting under FPTP, the voter must personally transfer their vote without it first being counted for the minority party the voter would prefer. The result of this is that the actual true support for the minority candidate is not reflected in the election result. The positive policy preferences of the tactical voter are left hidden. The major parties, which are inevitably the beneficiaries of tactical voting, carry on their chosen paths without reference to the real but hidden wishes of significant sections of the electorate.
Smaller but important parties are ignored, simply because they appear to have no support. As far as their true wishes are concerned, the tactical votes of the minority party supporters have gone down the drain.
The tactical voter has to guess where the most effective place for his vote is going to be. Remember while this is essentially their second preference vote it may up being cast for their third or fourth choice. The tactical vote is rarely a vote of support or preference. It will be a vote against the candidate the voter perceives as the less desirable potential winner.
While any form of voting is better than abstention, it is far better for people to vote for who they prefer rather than vote against those they dislike. That is why the 1,2,3 etc of AV is so important.
Finally and arguably the most important advance given by AV is that it is inclusive. It gives everyone a chance to see their vote count. People who would not bother voting because they dislike the concept of tactical voting, because of its usual negativity, will be enfranchised and more likely to vote.
The country is currently on a slippery downward slope. Less and less people vote in general elections and even fewer in council elections. Something must be done to defeat the apathy and re-enfranchise the disillusioned.
Tactical voting has some very large negatives associated with it. It is in no way a substitute for a proper transferable voting system like AV. AV is not perfect but it is far better than FPTP. AV is a way for the political establishment to re-engage with the electorate.
Vote for AV on May 5th.