I think it's the first series, cos it's never been on Terrestrial tv over here before (as far as i know anyway) I got this info from the 5 website:
Time - 19:15 - 20:50 (1 hour and 35 minutes long)
When - Saturday 21st September on Five
This programme has been highlighted due to keywords in the programme name
Pilot. Series 1, episode 1.
Feature length episode of the sci-fi drama series set in 2019, after a shockwave has left the US languishing in poverty. Max, a genetically enhanced human prototype being hunted by her former handlers in the military, encounters a cyberjournalist who attempts to enlist her in his own struggle
Starring: Jessica Alba, Michael Weatherly, John Savage, Valarie Rae Miller, Jennifer Blanc, Richard Gunn
(New Series, Subtitles, Stereo, 5 Star)