The Alternative Vote (AV) system seems at first sight to offer a plausible improvement over the current, very unrepresentative First-past-The-Post (FPTP) system.

However, various simulations run using the AVOTER simulation program suggest that in practice it would make little difference, producing a change of elected MP in just 22 out of 649 constituencies (not counting the Speaker's seat, which carries no votes and would not in this instance have changed MP).

At the same time, the expense involved in counting and re-counting voting papers, and the consequent delay in producing a result, is enormous. If the May 2011 referendum had decided (amusingly, by using a First-Past-The-Post selection system with only two alternatives!) in favour of AV, then almost nothing would have been achieved:

  • The simulations showed that a large proportion of candidates already collect more than 50% of the votes on the first round, and so all alternative votes in their constituencies would be totally ignored.

  • While it could be argued that AV would encourage people to vote other than for the "safe" candidate, it would only have a significant effect in marginal seats, and even here the simulations suggested relatively few changes.

  • It is difficult to see why having your first choice eliminated and your second-, third-, or fourth-choice candidate elected is really more "representational".

  • The voting in the House would still be just as skewed as it is under First-Past-The-Post: an MP from a small constituency who only just scraped in with a very small proportion of the votes would carry exactly the same voting power as an MP who polled, say, 60% of the votes in a large constituency. It should be noted that while AV claims to require a minimum of 50% of the constituency votes for the successful candidate, in fact - due to the discarding of alternative votes at each round - the final numbers are nearly always below 50%.

    • The AVOTER simulation results

    Tables summarising the simulation results are included for the UK as a whole and region-by-region, and are then set out in more detail constituency-by-constituency for each national region in the UK, with the equivalent tables for AV and ProFirst results being accessible by clicking the appropriate "ProFirst" or "AV" button in the index.

    Changes in the MP elected under AV compared with First-Past-The-Post or ProFirst are highlighted in the tables - for instance in the Edinburgh South constituency.