On Mon, 8 Jun 2015 17:17:01 +1000 John Chance wrote :
Because the alternative makes coalition governments inevitable
and mostly produces very unstable government as well. In some
cases like Belgium, they couldn’t even manage to form govt at all
for nearly two years.

There are two alternatives (with variants), often confused. One is
straight PR which more or less guarantees permanent coalitions, the
other AV - the subject of your last referendum - as used for lower
house elections here. Far from delivering unstable governments,
what is notable is that it tends to produce a house with very few
minor party candidates: our Victorian lower house splits 47/38/2,
Federal lower house 90/55/1/1.

That said, a couple of weeks ago there was a press story on what
effect AV would have had on the UK result, and IIRC the conclusion
was not a lot.

--
Tony Bryer, Greentram: 'Software to build on',
Melbourne, Australia www.greentram.com