Tonight's TV highlights

Everything and Nothing 9pm, BBC4 Professor Jim Al-Khalili's programmes are always worth watching, and not just to encourage the idea of having documentaries presented by people who know their subject. His new two-parter cannot be accused of lacking ambition. It's an attempt to survey humanity's efforts to unravel the big questions, ie, those pertaining to the size and shape of an infinite universe, and our humblingly insignificant place in it. Al-Khalili profiles the astronomers, mathematicians and sundry boffins who have pondered the fundamental truths of our existence. Andrew Mueller Twenty Twelve 10pm, BBC4 The second episode sees the Olympics Deliverance Committee on a hellish journey to meet Sebastian Coe at the Olympic stadium. After picking up delegates from Brazil's committee, the going gets slower and slower, allowing the team to deliver more of their trademark government-speak nonsense while Graham, Head Of Infrastructure, turns into a punishing backseat driver. It's a good mix of The Thick Of It and People Like Us, two shows this shares its DNA with. Phelim O'Neill Spartacus: Gods of the Arena 10pm, Sky1 When Andy Whitfield, lead in Spartacus: Blood And Sand, was forced to leave the role due to his cancer treatment, this mini-series prequel didn't sound like much consolation for fans. But, as anyone who stuck with the original from inauspicious beginning to thrilling and quite brilliant end should know, Spartacus is all about confounding expectations. Followers will meet all their favourite characters as earlier, less brutal versions. Newcomers should try to miss the opening couple of minutes, which deliver a spoiler-filled recap of the previous show. By the end, though, all should be completely hooked. PO'N Dispatches: Train Journeys from Hell 8pm, Channel 4 No marks for the hackneyed programme title but unlike some of the trains, it is at least direct. Actor Richard Wilson removes his foot from the grave, so to speak, and investigates the wealth of complaints by commuters against a British rail network upon which billions has been lavished, which charges higher than ever ticket prices and yet is still blighted by overcrowded carriages and cancellations. He talks to industry insiders and experts as well as long-suffering commuters, who get to tell their horror stories. A case for renationalisation? David Stubbs The Secret War on Terror 9pm, BBC2 Second and concluding part of Peter Taylor's survey of the defining geopolitical event of our times. Last week, Taylor focused on what might politely be called old-school methods employed by the United States and the west: arbitrary detention, secret prisons, outright torture. Tonight, he considers the present and possible futures, speaking to intelligence officials and politicians. As the "war on terror" nears its 10th anniversary, the key question is maddeningly ambiguous – are we winning? AM Law & Order: UK 9pm, ITV1 Every week in L&O, a clunky script is made to sing by an accomplished cast. But tonight the show is stolen from under everyone's noses by relative newcomer Benedict Wong, playing a defence lawyer representing someone who may – or may not – have committed a horrific murder as a 10-year-old, and who may – or may not – have committed another murder under his new identity. Suffice to say, this week's episode has more twists than a bucket of snakes at a Chubby Checker concert. Ali Catterall