Tonight's TV highlights

Bang Goes the Theory 7.30pm, BBC1 What's that WSSSSSHH sound? It's the collective sound of popular science fans drawing breath at the return of BGTT. In this first episode, the team explore the repercussions of the BP oil spill and entertain the general public with science experiments involving Russian dolls and weighing scales. The best bit comes when presenter Dallas Campbell, who is travelling to New Zealand with an atomic clock (the most accurate timepiece available) to illustrate the theory of relativity, declares: "It's worse than travelling with a small child!" Gilbert And Sullivan: A Motley Pair 8pm, Sky Arts 2 A great opening to a five-part series about Britain's greatest librettist/composer duo. Veteran G&S player Simon Butteriss presents with an appropriate level of whimsy and theatrics as he delves into the origins of WS and Arthur's topsy-turvy partnership. Subtle points of satire are acted out by professionals and amateurs (like Cambridge University's G&S Society) and their role in the development of musical theatre is explained by talking heads Michael Ball and Germaine Greer. Time Shift: The North On A Plate 9pm, BBC4 Andrew Hussey is a cultural history professor who lives in Paris. Originally from Liverpool, he wants to see if he can translate the French concept of terroirs, which denotes the geography and local conditions that defines distinct regional foods, to the north of England. And it's not so difficult. In Liverpool he instantly identifies lobscouse, a stew originally eaten by Baltic sailors and eponymous with the city, while he uncovers the historical link between Wigan and pies. His examples may not seem as glamorous as Bordeaux wine or camembert, but potatoes, fish and chips, tripe are all contenders for terroirs status. Mad Men 10pm, BBC4 "Who is Don Draper?" asks a reporter from Advertising Age in the first line of this fourth series, set in 1964. It's a knowing wink to an audience well aware of Don's dual life, but it presents a real problem for the ad man – as the public face of a new firm, Draper is now being asked questions about his background. And stonewalling them won't help a business so short of cash that it can't afford a conference table. Meanwhile Betty – who never had to worry about mother-in-law issues – is struggling under Henry's mother's scrutiny at Thanksgiving dinner. Derren Brown Live 10pm, Channel 4 Last time round, Derren Brown didn't just mess with the minds of a studio audience, he actually came after the viewer at home: in a moment that was as satirical as it was magical, he left members of the public unable to move from their sofas. Details about this new illusion (Stunt? Experience? Trick?) are of course under lock and key ("A member of the public goes on a life-changing journey"), but Brown's genius is in the pre-sale. Never mind what you actually see, Brown tells you that what you're going to experience is going to be pretty incredible. Words Of The Blitz 10.35pm, ITV1 More blitz commemorations, this time as told through the diaries and letters of those who witnessed the bombing of London firsthand. There's a mixture of class, age, sex: men and women, teenagers, fire fighters, nurses and government officials reveal their experiences and personal thoughts. There's fear and horror, of course, but also boredom and excitement; some are direct and descriptive, others poetic and elegiac. Actors, including Dominic West, Romola Garai, Sheila Hancock and Steven Berkoff, provide the readings. MS Previews by Megan Clarke, Will Dean and John Robinson