SIMON KERNICK'S series and standalones are all London Gangland Tales
Mike Ripley's ANGEL SERIES - Comic crime London Cabbie
Derek Raymond - Tough Noir in his Factory Series
Mark Billingham - Tom Thorne DI series
Mark Timlin - 'Sarf London with Nick Sharman
Ken Bruen's - Brant series
As well as heartily endorsing Ali's suggestions (apart from Timlin who I've never read, there are also:
Dreda Say Mitchell's tough inner city books
Christopher Fowler's humourous Bryant and May series
Martina Cole's criminal underworld standalones
And there are all manner of historicals set in London (including my favourite - Tony Broadbent's THE SMOKE)
For historicals, you might also try Jacquelin Winspear's series: Mazie Dobbs ... female detective, injured during WW I for early ones in series. I just heard her speak at booksigning about her interest in WW I, bought her Messenger of Truth, set later, 1931 in midst of Depression.
I read Tony BROADBENT,s THE SMOKE and loved it . It really moved along and I really enjoyed the characters , is this a series I'd really like to read more.Martina COLE's CLOSE was fantastic but I see why someone mentioned you have to take a bit of time before reading another I almost felt a little beat up myself after finishing it.Perhaps Christopher FOWLER's Bryant for a little lightening up . Thanks for the recommends they've been right on the mark.
Donna mentioned Martina Cole, and I have to say her stuff is phenomenal. East End London stuff that will break your heart and churn your stomach. You can't read too many in a row, though. But she knows how to pack a punch.
Just read Ms.COLE's CLOSE I loved it but I see what you mean when you say you can't read to many in a row.I will be reading more of them though I will wait a bit pack.Packs a punch alright , I feel like I've been thoroughly worked over.