His books included The Meaning of David Cameron (2010), Unhitched (2013), Against Austerity (2014) and Corbyn: The Strange Rebirth of Radical Politics (2016).

[3] His thesis, dated 2016, was titled Cold War anticommunism and the defence of white supremacy in the southern United States.

[10] Seymour writes about "issues such as imperialism, Zionism, Islamophobia and anti-capitalism, and covers strikes and protests with footage, images and reportage".

[11] He announced his resignation from the SWP on 11 March,[12][13] and began using the original blog to convey a more thorough account of the party's crisis than hitherto.

[25] In contrast, columnist Oliver Kamm, writing for his Times blog accused Seymour of historiographical distortions.

[28] Unhitched, published in 2013, focuses on Christopher Hitchens's work on religion, his engagement with British politics and his alleged embrace of American imperialism.

[34][35] On 2 September 2015, in a private Facebook comment on a Daily Telegraph column detailing Falklands War veteran and serious burns victim Simon Weston's remarks regarding then Labour Party Leadership candidate Jeremy Corbyn's plan, Weston believes, to "surrender" the Falkland Islands to Argentina, Seymour wrote: "If he knew anything, he'd still have his face".

[37][39] Seymour was a speaker at a September 2016 event in Liverpool organised by the Momentum group which coincided with the Labour Party's conference in the city.