Last Night's Viewing: Bob Servant Independent, BBC4 Life after War: Haunted by Helmand, BBC3

Bob Servant apparently owes his existence to email scammers. Like Henry Root, Willie Donaldson's imaginary letter writer, Servant was Neil Forsyth's alter ego in writing to online swindlers and con men, responding to them with a garrulous energy that drove even the most persistent of them to the point of distraction in the end.

Conceived as an act of subversive revenge against the tricksters, he's now been bodied forth by Brian Cox in Bob Servant Independent, a BBC Scotland comedy about Bob's attempt to be elected as MP for Broughty Ferry, a suburb of Dundee. Bob believes that he's one of nature's leaders, not a follower. "I'm not a punter. Never have been, never will be," he tells his gormless political assistant (formerly Director of Sauces for Bob's burger-van company). "I look at your Obamas and your Gandhis and your Burt Reynolds and I think, 'That's my mob, that's my mob right there'."

The opening sequence of Forsyth's comedy was very nicely done, a tour of Bob's smart conservatory looking out on the estuary of the Tay, which teasingly steered clear of Cox's face in favour of the trophies of Bob's business life and shots of his hands as he sketched out the path to power. His electoral strategy is simple. Talk to the young people and then "they'll phone the internet" and spread the word for him. He has boundless energy, limitless confidence in his own abilities and an election poster: "Vote for Bob Servant – because you know him and he's OK". But he does have one liability – his mouth. Every time Bob opens it he loses more votes. So eager is he to please the first caller to the radio show he appears on that he ends up pledging to shoot any dogs that enter a local park. When the police are called he's indignant: "That was a metaphor," he protests. "A metaphor for what?" asks the policeman. "Life," replies Bob after a brief pause.

There are rough edges here, but Cox speeds you past them by the ebullience of his performance, and quite often I found myself simultaneously thinking that it was all getting a bit silly and laughing at it at the same time. There's something joyfully inventive about Bob's foolishness too, a sideways skitter that keeps throwing up lines you couldn't quite have predicted. Trying to spin himself out of trouble with the enraged dog owners of Broughty Ferry, Bob goes back on the radio to insist that he's been taken out of context and is himself grieving for a lost dog called Dancer. "Do you have a description of Dancer?" asks the sceptical DJ. "Oh... he just loves life," replies Bob. Hard to categorise, but the fact that it is is one of its pleasures.

Life after War: Haunted by Helmand followed some of the surviving soldiers from one of the bloodier engagements of the war in Afghanistan – an ambush that left five soldiers from a patrol dead and several more seriously injured. Some of the wounds are physical – the group's commander, Alex, had lost a leg and a hand in an explosion – and others are mental, with recurrent nightmares, flashbacks and depression afflicting the survivors. One soldier found it hard to shake a fear of IEDs, even when walking through a west London shopping centre. A loose drain cover or a sudden noise would jolt him back to Helmand. Another hadn't had an unbroken night's sleep for three years.

Michael Price's film properly reminded you that the dangers don't stop when the troops get back, but it was a little marred by wishful thinking – or at least television's addiction to the upbeat conclusion. "The reunion has achieved everything that Alex hoped for," the voiceover said about the meeting that gave the film a climax. Everything? Really? With several of his men still struggling with mental- health problems? I somehow doubt that, however one might hope it was the truth.

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