Posted on 31 January 2018
Born in Beverley, East Yorkshire in 1952, Dunmore studied English at the University of York in the early 1970s.
Inside the Wave considers her terminal cancer diagnosis and impending death. After her death, the collection was updated to include the poem Hold Out Your Arms, written just ten days before she died.
The overall winner is chosen from five books which had already won prizes in the categories of novel, first novel, biography, poetry and children's book.
The ceremony, previously known as the Whitbread Book Awards, has taken place annually since 1971.
Judges described the collection as "an astonishing set of poems - a final, great achievement".
Dunmore is the second writer to win the overall prize posthumously, following Ted Hughes in 1998.
Inside the Wave is the eighth poetry collection to take the overall prize and beat the favourite Eleanor Oliphant is Completely Fine to take the title.
Dunmore is the author of 12 novels and ten poetry collections.