BBC Four HD

Programmes start at 7.00pm.

The semi-finals of the tournament begin. The first of the four remaining teams do battle for a place in the series final. Jeremy Paxman asks the questions.

Quiz show in which connections must be made between seemingly random subjects. Three gamblers take on a team unified by their love of ten-pin bowling.

Professor Brian Cox journeys into a supermassive black hole - a monster that can destroy worlds and stop time, and which is forcing us to reassess our understanding of reality.

An insight into the Nazis' reign of terror in Poland. Contains some scenes which some viewers may find upsetting.

Lucinda Lambton visits Europe's last ornamental farm, at Larchill, west of Dublin. It features rustic follies, great lakes and a glorious collection of animals.

.. Our Friends in the North. Christopher Eccleston reflects on the making of Peter Flannery's acclaimed 1996 drama. Contains some strong language.

The friends' reunion is a disaster. Contains some strong language.

The world has turned sour for the gang. Geordie is in jail, and Tosker works in a factory. Contains some strong language and some scenes of a sexual nature.

Quiz show in which connections must be made between seemingly random subjects. Three gamblers take on a team unified by their love of ten-pin bowling.

An insight into the Nazis' reign of terror in Poland. Contains some scenes which some viewers may find upsetting.

Professor Brian Cox journeys into a supermassive black hole - a monster that can destroy worlds and stop time, and which is forcing us to reassess our understanding of reality.

Programmes start at 7.00pm.

Programmes start at 7.00pm.

In the second of the series semi-finals, two more teams of students face off for a place in the grand final. Jeremy Paxman asks the questions.

Quiz show with Victoria Coren. In the first semi-final, three lovers of the pastoral world of The Archers face a team of confirmed gamblers.

Classic period drama about three children whose lives change dramatically after they move from a comfortable townhouse to a small Yorkshire cottage near a railway line.

Ben Fogle travels to West Yorkshire with actress Sally Thomsett to visit the locations of key scenes from the classic 1970 film The Railway Children.

A power repairman has an encounter with a spacecraft and is obsessed with seeing it again. Contains language which some may find offensive.

Quiz show with Victoria Coren. In the first semi-final, three lovers of the pastoral world of The Archers face a team of confirmed gamblers.

Grammy-winning sensation Samara Joy sings timeless and much-loved classics.

Programmes start at 7.00pm.

Programmes start at 7.00pm.

Jamie Theakston presents the pop chart programme, featuring Pet Shop Boys, Donell Jones, Point Break, Missy 'Misdemeanor' Elliott, Eurythmics, Scooch and Manic Street Preachers.

Jamie Theakston presents the pop chart programme, featuring Donell Jones, Nu Generation, Super Furry Animals, Hi-Gate, Manic Street Preachers, Scanty Sandwich and Britney Spears.

Janice Long presents the pop chart programme, first broadcast on 3 July 1986. Featuring The Housemartins, Samantha Fox, Claire & Friends, Sly Fox, Gary Numan, Bucks Fizz and Wham.

Nicky Campbell presents the pop chart programme, first broadcast on 6 July 1989 and featuring Sonia, Monie Love and The Beautiful South.

As Adam Frost's brand new garden starts to take shape, it's time to get some shrubs in the ground and construct a path.

including Jackson Browne, Nanci Griffith and Loudon Wainwright - perform one of their key songs and explain how they came to write it.

Jackson Browne in a live concert from the BBC Television Theatre, London. Introduced by Bob Harris.

An acoustic performance by Nanci Griffith, Rosanne Cash and Mary-Chapin Carpenter.