Helen Dunmore’s final poetry collection Inside the Wave has won the overall £30,000 Costa book award, it was announced on Tuesday. The poems within Inside The Wave are described by publisher Bloodaxe as being “concerned with the borderline between the living and the dead – the underworld and the human living world.” The Costa judges called them "an astonishing set of poems - a final, great achievement".

Helen Dunmore died of cancer earlier this year at the age of 64. She was a novelist, short story and children’s writer, as well as a poet, and won first prize in the National Poetry Competition in 2010 with ‘The Malarkey’.

She is only the second writer to win the prestigious award posthumously, following Ted Hughes who won in 1998 for Birthday Letters. The poetry category last won the overall Costa prize in 2012, with Jo Shapcott’s Of Mutability.

The chair of the judges, Wendy Holden, said Inside the Wave was “a modern classic ... even though it was written while she was dying, it was very life-affirming".

Dunmore’s win will hopefully help place poetry back in the public eye, “particularly as poetry is at a very interesting place at the moment, as it is very hotly debated what poetry is, now, whether it is slam poetry or, in inverted commas, highbrow,” Holden added.

Helen Dunmore’s husband Frank Charnley and their children Patrick and Tess went on stage to receive the award, at the ceremony in London on Tuesday night.