Mental health nurse Nathan Filer is returning to his next shift £30,000 better off after winning the Costa Book Award for his first novel The Shock of the Fall.

Filer, who also teaches creative writing at Bath Spa University, drew on his background for his novel about two brothers torn apart by a tragic accident and the slow descent of one into schizophrenia.

But speaking after he picked up the award in central London, he said the book was not about a "campaign" to raise awareness.

He said: "I didn't set out to write about mental illness or schizophrenia, I set out to write about this character and his illness is one aspect of his character and there are many more than that".

The 33-year-old, who is still a registered nurse working in and around his hometown of Bristol, said there was "something to be said about having more to your life" than writing.

He said: "I do do shifts at the hospital and I've got one coming up next Sunday".

He said he was also working on another book but stayed tight-lipped about the details.

Novelist Rose Tremain, who chaired the judging panel, praised the book as "astonishingly sure-footed" for a first novel.

It is the first time a debut novel has won the prestigious prize since Stef Penney's The Tenderness of Wolves in 2006.

Ms Tremain said the book was about grief.

She said: "This is a subject which we all have experience of and it is grief analysed but treated absolutely without sentimentality".

She compared it to Mark Haddon's best-seller The Curious Incident of the Dog in the Night-time, saying there had been "much discussion" about the other books in contention but said Filer's book "stood out in an exceptional way".

She said: "As we know the Costa Prize is important and this is going to change this person's life".

A spokesman for booksellers Waterstones said: "This is a real giant killer of a winner, and shows the Costa is as exciting as the other major literary prizes. While The Pike was a strong second favourite, the Costa does not favour biography so the smart money was on Life After Life. But Atkinsons was not the only book people were reading and, essentially, talking about in 2013. This will make The Shock of the Fall a major best seller, and put its multi talented author firmly on the literary map."