Why does seven-year-old Jay's playfighting with baby brother Owen always turn nasty? Psychologist Dr Tanya Byron offers an intriguing explanation for his bully-boy behaviour.

*** William Shatner makes his directorial debut in the fifth spirvoff from the hit sci-fi TV series. The crew of the Enterprise encounter a messianic figure holding a planet hostage. Co-starring Leonard Nimoy and DeForest Kelley.

How will the public react to the comedy trio's cheeky stunts?

5/6. Emily and Florence decide to play tennis.
Guest-starring Anthony Head plus Jon Culshaw from Dead Ringers.
Tom Baker narrates. (AD) BBCi: features available via the red button www.bbc.co.uk/littlebritain

3/6. Continuing the dark, pacey drama about a police murder investigation. Chrissie finds a witness from the night that
Jason Buliegh went missing.

4/6. A dramatic turn of events sees Chrissie and Joe hailed as heroes - but still haunted by feelings of guilt. The series concludes tomorrow at 9pm