I was just in London for New Years and didn't bump into any gangs or anything...man I must've been going to the wrong places!!!
EVERY big city has high crime rates - and if you choose to live in fear and miss out on life then how sad is that!
So hapy - since no-one so far has given you place names here goes - Covent Garden, Piccadily, Regent St, Oxford St, Holland Park, Notting Hill, Kensington, Chelsea, Putney, Embankment, South Bank, Greenwich - all good, lots to do - great nightlife, easy public transport and good fun!