The mystery is solved here. Look under DEFRA. Isn't it just typical of Westminster villagers who reported Tessa Jowell as the minister responsible to lump London and the South East together - no political nous? That goes for the PMOS PMS too - he set this hare running according to the Morning Lobby briefing on 28 June, but then he can be forgiven - he's a civil servant.
The PMS said that also attending Cabinet were Minister for the Olympics, and London and the South East was Tessa Jowell
I suspected this was a lot of tosh immediately from the formal listing on the No. 10 website shortly after it was published, as I wrote here. Why not add a link to this site on yours?