TV episode review
UK airdate 23 April 2010 (BBC One)

WARNING: Contains possible spoilers!

Gene is not at all happy to discover that an undercover operation has been running on his patch...

The setting may have been moved forward to 1983, but this is one of the best Sweeney clone episodes that the Life on Mars/Ashes to Ashes franchise has produced, with the added layer that Jim Keats sees a chance to spread more dissension.

While the "Who killed Sam Tyler?" plotline bubbles along beneath the surface, this week's story concentrates firmly on an undercover officer who feels betrayed by her controller on the force. This allows for a lot more genuine Hunt bluster, gives Alex a chance to display her empathetic skills... and unfortunately appeals to Chris Skelton's sense of chivalry.

It's sometimes seemed this season as if Chris's betrayal of everyone last year has been completely forgiven and forgotten, but the character's inherent weaknesses are once again his undoing when he is manipulated into doing someone else's dirty work. And of course weaknesses are what Jim Keats is thriving on – but rather than simply take the chance to break up Gene's team by getting rid of Chris, Keats has a much more insidious plan...

Ashes to Ashes may have taken its time finding its feet, but this season is proving to be must-see television. Paul Simpson

VERDICT: 8/10