Walk more. Since I started to walk from Victoria to the office each morning (just over 2 miles) back in October, I've dropped a dress size. I don't know how much weight I've actually lost because I hate being weighed, but the looser clothes and needing new jeans because I could pull my old ones down without undoing the zip are a good indication that it's working :-D I also feel a lot better in myself.

Once the nights are lighter I'm going to walk back in the evenings too as it's far better than squeezing onto a sweaty tube.