Announced at the Groucho Club in London on the eve of National Poetry Day, the Forward Prize - the country's most lucrative award for poetry - pushes Hughes's earnings from British literary prizes this year to well over pounds 40,000. His previous volume, Tales from Ovid, has won both the Whitbread Book of the Year award and the W H Smith literary award for 1998.
Birthday Letters, Hughes's intense verse account of his marriage to the American poet Sylvia Plath, who committed suicide in 1962, burst on to the literary scene in the new year. Hughes's publisher, Faber & Faber, and The Times, which bought the rights to print extracts from the work for a six-figure sum, maintained a strict silence up to publication.
Friends and colleagues had known that the 68-year old Hughes, who lives in mid-Devon with his second wife, had composed some poems that reflected his troubled life with Plath, from their courtship at Cambridge to the disastrous aftermath of his affairs. But the range and quality of the verse narrative in Birthday Letters astounded many critics. Seamus Heaney called the sequence of poems "miraculous" while Tom Paulin hailed a "visionary" work. Its huge sales, unprecedented in number and speed for a volume of verse in Britain this century, saw Birthday Letters head the non-fiction charts for almost two months.
One of the few dissenting notes came in The Independent. Ruth Padel, winner of last year's National Poetry Award, admired Hughes's "searing autobiography" but found the work "humanly shattering, poetically inert". She concluded that "to call this his masterpiece is to deny his own gold standard".
The other winners of Forward Prizes were Paul Farley, whose book The Boy from the Chemist is Here to See You was awarded pounds 5,000 for the best first collection, and Sheenagh Pugh, who won pounds 1,000 for the best single poem, beating a shortlist including Douglas Dunn, Paul Muldoon and Peter Porter.