It the last election, John Bercow (speaker seeking re-election) was subject to much controversy, he has entered parliament as a hard right Conservative, but (supposedly on realising he was not going to get to the top of the party) had drifted further and further to the left - when elected speaker it was as a result of Labour MPs votes and was commonly seen as a 'spite' against the Conservative MPs.
Jonh Bercow was(/is) not popular among conservatives, even in his own constituency. He was opposed in his re-election by a former conservative councillor who ran against him as an 'Buckinghamshire Campaign for Democracy' candidate (an 'independent conservative'), and by Nigel Farrage former (and current) leader of the UK Independence Party (UKIP).
The result was: (from wikipedia)
|General Election 2010: Buckingham,|
|Buckinghamshire Campaign for Democracy||John Stevens||10,331||21.4||N/A|
If we assume that these would be fairly representative of peoples fist preference votes (had it been an AV election)...
I think it fair to say that under AV here would be no reason to think Bercow would get more 1st preferences. Also that under AV he would probably have received fewer 1st preferences. As some who voted for him may well have preferred another candidate but were worried about splitting the Conservative vote and 'letting in' a non-conservative - a worry that would not exist under AV.
Assuming UKIP voters would have preferred John Stevens to John Bercow, it would only have taken about 3000 Bercow voters to give John Stevens a higher preference for John Stevens to have won and Bercow to have lost his seat.
Just think, no Sally Bercow on our screens all the time! No soft porn photos of her over the Thames in front of the House of Commons -- don't you wish we had AV already?