After the same result in 2008 they looked angry, shell-shocked and a little lost at being in opposition for the first time.
Even between 2000-2003 when Ken Livingstone was an independent he still dished out jobs to Labour AMs and had cordial relationships with most of the group.
Shadowing him on polling day 2008, Ken told me if he lost the Labour group would do a fine job of holding Boris to account both inside and outside the Chamber.
Labour AMs certainly asked some tough questions during Boris’s first four years but Ken’s prediction of them holding him to account outside City Hall – by which I assume he meant in the media – never really had a chance to come true.
By turning up at Boris’s very first Mayor’s Question Time Ken ensured he squeezed the group even further out of the limelight.
From that day on he was, as I suggested to him at the time, the unofficial leader of London’s opposition. There was never any room in the capital’s political debate for anyone other then Ken or Boris.
All of us in the media salivated at the prospect of a 2012 re-match.
By the time Livingstone was selected as Labour candidate for this month’s elections the Labour AMs often looked like mere pawns in his game, asking questions of Boris designed to score points to aid Livingstone’s re-election.
But, to the almost equal delight and dismay of Londoners, Livingstone is no longer part of London’s political narrative.
His involvement in London’s political story ends with a second defeat while the Labour Assembly group are celebrating the gain of four additional colleagues and the decapitation of two of Boris’s top appointees.
With 12 AMs of their own and 4 co-operative Greens and LibDems the Labour group will control the Assembly for the current term.
Tory walkouts will rarely bring proceedings to an end and motions condemning the Mayor, his policies and appointees are virtually guaranteed to pass.
That, Tory voices claim, is the true point of last week’s agreement which commits Labour to supporting additional resources for the two smaller parties.
Towards the end of this term Labour will pick a Mayoral hopeful but for now Len Duvall, John Biggs, Val Shawcross and their colleagues are the biggest Labour beasts in London politics.
There’s no-one else in the party for the media to go to – no-one else has a mandate to oppose or criticise Boris.
Is it possible that the cheery spirits I noticed last week stem from the realisation that they’re no longer in Livingstone’s shadow?
