Although the London Mayor still relies on central government for the vast majority of the money spent running the capital, big decisions are made by the Mayor in the two critical areas of transport and crime.
Boris and the boroughs are also making a strong play for more of the health budget and so, apart perhaps from social services and education – where Boris has said little and is able to do less about the current debate over welfare reform and schools funding – you have three major election issues directly influenced by the Mayor.
Boris has of course already declared his candidacy for a second term and started setting up his campaign team.
The fact that he has done so before the party conferences, when he will make a keynote speech, and before the spending review in October, suggests he has something good to launch his campaign with – perhaps the deal with George Osborne on how much London has got?
So how will Ken or Oona respond to this? How will they play the cuts London will inevitably have to face, in many cases in its most deprived areas? Not to mention what the Lib Dems might do.
The answer of course is that whoever wins Labour’s Mayoral candidacy will have to do their own version of the Boris and George deal, which will be the most immediate, most critical agreement to be made by the new Mayoral candidate and their new party leader.
This deal will determine the battle over public spending in London on key voter issues and, ultimately therefore, how the next Mayoral and general elections will be fought.
Luke Blair is a director at London Communications Agency