YouGov, London: Lab 44, Con 32, UKIP 10, Lib Dems 8, Greens 5
Also, 78% say they are 'absolutely certain' to vote, which is higher than the UK as a whole (around 70%) but below Scotland (over 80%).
Why are the Greens not stronger in London? Is Labour poaching potential Green voters because of the tightness of the polling?
I'm addition to what Al said, the Greens are targeting surprisingly little London seats. (For example, even on their very optimstic list of 12 target seats, the only London one I noticed was Holborn and St Pancras. Other London seats where Greens have had ephemeral success or favourable demographics (e.g areas of Lewisham, Haringey, Islington etc. seem to have less invested in than non-London student filled areas - Oxford W, Cambridge, Norwich S, Sheffield C etc. Heck, the Greens are throwing more at such inexplicable locales as St Ives, Reading E and Solihull than at London)
its more trying to increase council seats at the same time as getting a good parliamentary vote, if the London Boroughs were up for election this year we'd be putting a lot more effort into six or so target seats in London
we have 3 cllrs in reading (hopefully to become 4) a fair amount of students and a collapsing LD vote, 4 cllrs in the Solihul constituency (plus 3 in the part of the borough that's in the Meriden seat)
