They were 'Cudlipp' and 'Mr King' when they met in 1935. At 21, gregarious, extrovert and irreverent Hugh Cudlipp had many years of journalistic experience: at 34, shy, introspective and solemn Cecil Harmsworth King, haunted by the ghost of Uncle Alfred, Lord Northcliffe, the great press magnate, and bitter towards Uncle Harold, Lord Rothermere of the Daily Mail, was fighting his way up in the family business.

Opposites in most respects, they were complementary in talents and had in common a deep concern for the underdog. Cudlipp, the journalistic genius, and King, the formidable intellect, were to become, in Cudlipp's words, 'the Barnum and Bailey' of Fleet Street. Together, on the foundation of the populist Daily Mirror, they created the biggest publishing empire in the world.

Yet their relationship foundered sensationally in 1968, when - as King tried to topple the Prime Minister - Cudlipp toppled King. Through the story of two extraordinary men, Ruth Dudley Edwards gives us a riveting portrait of Fleet Street in its heyday.