[seabee]

Bear in mind that Labour offered AV with no referendum necessary, but did not have the seats to form a majority with the Lib Dems alone. Had they upped their offer to (a referendum on) PR it would have had the support of the minor parties and likely would've passed; however, all other issues would face severe compromise and difficulty, so being in opposition benefits Labour (a party that doesn't need PR, even if it desires it) in the long-term.

Minority governments do not last very long and with Labour on the wane there was a significant possibility of a subsequent election giving the Conservatives a majority; at best, there would be an opportunity for a Lib-Lab majority. The Liberals' power is often overstated by principled idealists, but for pragmatists it was a good choice: 75% of their manifesto is becoming Government policy, compared to 60% of the Conservative manifesto (http://guildfordlibdems.org.uk/en/article/2011/486213/75-of-...). Of course, the remaining 25% matters a lot more to many people than the 75% they implemented...

[dazzawazza]

It's also important to remember that neither the Lib Dems nor Labour could afford another general election.

[Super_Jambo]

Given Labour had 12 years of solid majority government, in which time they had a mandate from the electorate for electoral reform (manifesto promise). And given the No camp has more Labour MPs than the Yes.

I feel you cannot state that Labour in any way desires electoral reform.