BBC Four HD SkyTV

Programmes start at 7.00pm. [HD]

Post-war architectural innovations in the Big Apple. [S]

Kenneth Williams stands in for Terry Wogan, chatting with guests Barbara Windsor and husband Steve Hollings, Stephen Fry and Michael Palin. Music by Hank Marvin & The Shadows. [S]

Documentary exploring Britain's funniest and most complex comic performer. Deals with adult themes. [S]

Kenneth Williams explores his roots in and around London's St Pancras, where he grew up. [S]

Documentary following undercover police as they investigate online crime against children. Contains some strong language and disturbing scenes. [S] [HD]

A Storyville documentary that follows a Russian schoolteacher as he risks everything to expose rising militarism in his classroom. Contains some strong language. [S] [HD]

Documentary exploring Britain's funniest and most complex comic performer. Contains some strong language. [S]

5/17. The story of how our solar system will be transformed by the ageing sun before coming to a spectacular end in about eight billion years. [S,SL] [HD]

Programmes start at 7.00pm. [HD]

Programmes start at 7.00pm. [HD]

14/15. Michael finds out about the impact of a famous Enoch Powell speech across the nation. [S,AD] [HD]

1/5. Rugby legend Gareth Edwards and wife Maureen try steam trains and rallying in Machynlleth. [S] [HD]

4/4. Brian explores the enigma of time - a phenomenon that we take for granted but which, as far as physicists are concerned, is one of the biggest mysteries in the universe. [S,AD] [HD]

4/6. Bruce Parry spends time with the Akie people of Tanzania, who live on the savannah. Contains some strong language. [S,AD]

Sir Derek Jacobi looks back on the 1997 BBC drama about mathematician Alan Turing. [S] [HD]

Factual drama about Alan Turing, the mathematical genius who cracked the Enigma code. Deals with adult themes. [S]

2/3. Sam Willis tells the story of the English ruler who left the most indelible mark on the castle, Edward I, as he turned it into an instrument of colonisation. [S,AD] [HD]