Michael Portillo heads for leafy Hatch End, where he investigates an illustrator whose work was so popular in the 1920s and 30s that his name entered the English dictionary. William Heath Robinson’s great-nephew talks Michael through some of the mad contraptions the artist used to satirise technology.

Michael’s next stop is Slough, where after World War I, three businessmen established a world first: an out-of-town trading estate with rail connections, power, water and premises. Today, 350 businesses operate from there, and its success has been replicated across the world. Michael meets one long-standing customer, Mars, who have been manufacturing their chocolate bars in Slough since 1932.

Close by, in Stoke Poges, Michael visits a very different 1930s landmark, a unique and beautiful memorial garden comprising woodlands, rockeries and fountains. The Head Gardener enlists Michael’s help to plant a yew tree.

From Slough, Michael makes tracks along the short branch line, which serves two towns, Windsor and Eton Central. At Windsor, Michael surveys the great walls of the castle, chief residence of the British monarch and the oldest and largest occupied castle in the world. He looks back at the tumultuous events within those walls, when in 1936, King Edward VIII renounced the throne to marry an American divorcee. Show less