BBC Four HD Tuesday

Visits to historic places of work, including one of Britain's oldest dockyards in Chatham, Kent, and the discovery of an early form of fireproofing at Armley Mill in Leeds

Richard Holmes traces the events of the Battle of the Somme on July 1, 1916, when 57,000 Allied soldiers were killed or wounded in a matter of hours

Marjory resolves to protect a rare bird nesting on the estate - much to Audrey's annoyance. First shown in 1981

Hyacinth remains convinced that Emmet's shyness is the only reason she has not been cast in his latest musical. Patricia Routledge stars

Clare Jackson reveals how the unprecedented religious violence of the Wars of the Three Kingdoms shaped British political culture and subsequent constitutional crises

The story of CIA officer Peter Sichel - a Jewish refugee who fled Nazi Germany before becoming one of the most influential figures in American intelligence

Helen Czerski examines the complexities of colour, including what it is, how it works, and how it has written the story of the planet