"Sorry mate, I don't go sarf of the river". Well, maybe the cabbie's historic reticence to venture into south London is one of the things that's keeping it so green.
Data compiled by London Cleaning System shows that the eight greenest boroughs all lie south of the river. How did they measure what makes a borough so green? On five factors: recycling, air pollution, renewable energy, percentage of green space and energy efficiency.
So what's the winner? Sutton. It's not surprising that the boroughs on the fringe of Greater London doing best in the rankings.
There are a few surprises popping up in the data, for example, the City apparently has the lowest amount of air pollution. Despite its busy roads, the fact that the City's so small means that it produces fewer tonnes per year than other areas — although we'd like to see these stats take into account area size as well to level the playing field.
Another unexpected result is Tower Hamlets — though coming towards the bottom overall — which has the best energy efficiency score.
Take a look beneath to see how your borough did.