He has written biographies of Aneurin Bevan, Clement Attlee, Harold Macmillan, Gordon Brown[1] and Tony Blair.

He worked as a journalist, a teacher, an adult education lecturer, and West Midlands organiser for the housing charity Shelter, before becoming head of the press and publications department at the National Union of Students.

Beckett has written a biography of his own father, John, a Labour MP from 1925 to 1931 and whip of the Independent Labour Party group of MPs; later chief propagandist for Oswald Mosley's British Union of Fascists and co-founder (with William Joyce) of the National Socialist League, who was interned during the Second World War for his fascist activities.

His biography of Tony Blair, written with The Guardian's Westminster Correspondent David Hencke, is hostile and damaging, and his 2009 book, Marching to the Fault Line, also written with David Hencke, is according to Seumas Milne, "the first attempt since its immediate aftermath to offer a full account of the [miners'] strike.

"[7] It is, according to Neil Kinnock, "full of vital insights and written with a sense of pace that does justice to the tragic drama."

[9] In response, with co-author David Hencke, Beckett insisted that the writers were not jackals but lifelong trade unionists, and asserted that "for Murray to try to make out that you are doing something bad by buying or reading our book is not just censorship, but also the bitterest form of ideological rigidity and sectarianism".