Hollande - red of course 'cos of his politics.
Putin = khaki 'cos he seems so military.
Thatcher - blue: she wore it a lot, it's how she makes me feel, and she's Tory.
Gordon Brown - mud brown - he just is.
Tony Blair - red. I know he wasn't a red - pale pink at most, but somehow the colour suits him.
Merkel - green - don't know why. I suppose I think of Germany as green.
Cameron - blue. He just is.
Clegg - multi-coloured: I just can't pin him down.
Our own PM in Australia, Julia Gillard: red as in a red Welsh dragon.
Our opposition leader Tony Abbott - green as in budgies (sorry, it's an 'in' joke)
(Being a fitness fanatic he is often seen in swimmers, those brief ones which are called 'budgie smugglers' here)