Ashes to Ashes Season 3 Episode 8 (Ashes to Ashes s03e08) airs on Friday, May 21st 2010 at 09:00 pm via BBC One.
Here is summary for Ashes to Ashes Season 3 Episode 8 :

Gene and the team investigate a diamond heist following the murder of three London gang members. Alex remains determined to discover if Gene did kill Sam Tyler. After Alex disappears, Gene races off after her leaving Ray, Chris and Shaz to plan a sting operation.

Few hours after original series aired on TV, online streaming video for Ashes to Ashes Season 3 Episode 8 usually available on Net and of course, if video available, as soon as possible will show you where you can watch this episode for free.