The winner of a £1,000 prize for poetry in translation has returned the prize and withdrawn his entries, after allegations of plagiarism surfaced in a poetry news blog. Allen Prowle, a respected translator who had previously won the Stephen Spender prize for poetry in translation in 2007, was awarded the prize again last month for ‘Johnson Brothers Ltd’, a translation of a poem by Dutch poet Rutger Kopland. Another Kopland translation that was submitted by Prowle was commended.

News of Prowle’s withdrawal was first reported in The Bookseller magazine. Robina Pelham Burn, director, of the Stephen Spender Trust, told Write Out Loud: “All I can say is that Allen Prowle has withdrawn his poems and returned the prize money.” On its website the trust says that, following Prowle's withdrawal, no first prize is being awarded in the prize's open category this year.

The claims of plagiarism were made in the Dutch Nederlandse Poëzie Encyclopedie news blog, which alleged that “international research by poetry translators and specialists in plagiarism from the UK, Netherlands and Denmark” showed that “Allen Prowle … simply lifted five translations wrought by the late James Brockway and the living Willem Groenewegen from the internet, slightly adapted them and subsequently submitted them under his own name”.

The trust’s conditions of entry include these words: “Each translation must be the original work of the entrant and not a copy or substantial copy of someone else's translation; it must not have been previously published or broadcast.”

Prize judge Stephen Romer said initially after the prize was awarded: “The judges – Josephine Balmer, Katie Gramich, WN Herbert and myself – shortlisted all five of Allen Prowle’s superb translations of Dutch poet Rutger Kopland, and eventually chose as the winner the elegiac ‘Johnson Brothers Ltd’, a moving memory of the poet’s father.“

The Bookseller reported that Prowle could not be contacted for comment. The Stephen Spender prize for poetry in translation is run in association with the Guardian. Inviting entries to this year’s prize in January, the trust’s Robina Pelham Burn said: “Poetry translation requires an unusual degree of judgment and balance: while slavish fidelity rarely works, there is a thin line between inventiveness and travesty.”