Ken '08 = Kerry '04 and Gore 2000
The big lesson of this one is that despite a campaign that was really firing on all cylinders in the final weeks (all credit to Ken Clarke, London Region Labour Party Director) left candidates can't win unless they triangulate and take the centre ground.
Just like John Kerry and Al Gore (and probably in November Obama) we got our core vote hyped up into a frenzy and turnout shot up.
But you can't win an election in London, the UK, or the USA, just by enthusing Guardian readers, students and BME communities. There are other forces in society who are more numerous and will always go one better in turnout.
You have to have something to say to the white C1s and C2s in Havering and Croydon and Bexley. I never saw anything in Ken's messaging or positioning that acknowledged that these people were Londoners too and addressed their concerns directly - and in fact we boxed ourselves into a turnout battle against the suburbs - something that we were never going to win, rather than trying to get the kind of white van drivers who voted Blair in 1997 on side.
Ken's alienation of the Jewish community through the Finegold affair and inviting dodgy Islamist clerics to City Hall was also crass beyond belief - picking a stupid, tokenistic fight with a community whose instincts are liberal, who want to vote Labour, who take their democratic duties very seriously and will turn out - probably a large slice of Boris' margin of victory was Jewish voters alienated unnecessarily by Ken.
This doesn't just apply to London - we will not win the next General Election unless we occupy the centre ground, develop policies that resonate with the suburbs, the C1s and C2s and avoid the temptations of comfort zone politics. However great the campaign, however great the candidate, you can't win without triangulating. That's why Blair and Clinton won and Kerry, Gore, and tonight Livingstone, did not.