What is the best places to live if working in westminster?

It depends on your budget, mate. If you have lots of money, Pimlico is great. You can even walk to work. For something a bit cheaper, look south of the river. Places like Clapham or Balham are popular. They have a good vibe and quick trains into Victoria. Kennington is also a good shout. It is very close on the Victoria tube line and still a decent price.