Aquascutum

Aquascutum invented the first waterproof cloth in 1853 (hence the name), and their flagship store has a slightly Victorian air, with dignified, slightly snooty staff, materialising at your side to offer fashion advice and personal tailoring. Even if you can't afford to buy anything, its an exceptionally soothing shopping experience. Their clothes are a mixture of the highly fashionable and the absolutely timeless, with a particular emphasis on smart suits and, of course, overcoats.