Parallel stories: 18th century Harrison builds the marine chronometer for safe navigation at sea; 20th century Gould is obsessed with restoring it.

In 1880s London, pornographic bookseller Verloc is a double agent for the Russian government, providing information to Chief Inspector Heat about a lazy anarchist organization. In order for the anarchists to be arrested, an act of terrorism must occur. So Verloc decides to set up bombs – which leads to tragedy – not only for himself but also for his family, including wife Winnie and brother-in-law, Stevie.

Stephen Lawrence was a black London teenager murdered by white racists in 1993. His parents fought to have the crime properly investigated, culminating in a judicial enquiry into the event itself and also the inadequacies of the ensuing investigation by the London Metropolitan Police.

Boys’ canoe trip on the Thames in London.