4.4 The Sontaran Stratagem

Written by Helen Raynor
Directed by Douglas Mackinnon
Produced by Susie Liggat
Executive Producers:

• Russell T Davies
• Julie Gardner
• Phil Collinson

Length: 45 minutes

UNIT is investigating ATMOS, a new device which somehow cleanses the exhaust from automobiles. The Taskforce believes that ATMOS is alien technology, and so their newest recruit -- Martha Jones, now a fully-credentialled physician -- calls the Doctor back to Earth for assistance. ATMOS is purported to be the invention of child genius Luke Rattigan, but the Doctor soon discovers that Rattigan is working with the Sontarans, who have used ATMOS to turn four hundred million cars into deadly weapons.

Air Date: 26/04/08
Viewers (millions): 7.06

Cast:

• David Tennant (the Doctor)
• Catherine Tate (Donna Noble)
• Freema Agyeman (Martha Jones)

Guest Stars:

• Christopher Ryan (General Staal)
• Rupert Holliday Evans (Colonel Mace)
• Dan Starkey (Commander Skorr)
• Bernard Cribbins (Wilfred Mott)
• Jacqueline King (Sylvia Noble)
• Eleanor Matsuura (Jo Nakashima)
• Ryan Sampson (Luke Rattigan)
• Christian Cooke (Ross Jenkins)
• Clive Standen (Private Harris)
• Wesley Theobald (Private Gray)
• Ruari Mears (Clone)

Next Episode: The Poison Sky

Previous Episode: Planet of the Ood