A long-lost verse pamphlet by the great Romantic poet Percy Shelley, written in defence of an imprisoned Irish journalist, was unveiled on Tuesday at the Bodleian Library in Oxford. Shelley, one of the greatest English poets of the 19th century, wrote Poetical Essay on the Existing State of Things in autumn and winter 1810-11 during his first year as a student at Oxford.

It protests against Britain’s involvement in the Napoleonic war and in particular supports the Irish journalist Peter Finnerty, who was accused of libel by the government and imprisoned after criticising disastrous British military operations in Denmark.

Shelley’s 10-page poem was considered lost until 2006, when a single copy was discovered in a private collection. Only now, with the acquisition of this unique copy by the library, has the text been made public. The actress Vanessa Redgrave read it aloud at an event in Oxford on Tuesday evening.

Finnerty, whose name appears prominently on the title page, is thought to have been born in Loughrea, Co Galway, and was associated with the revolutionaries of the United Irishmen. He was imprisoned in Dublin in 1798 for seditious libel after he attacked judges who sentenced other members of the society to death. He emigrated to London, where he worked as a parliamentary reporter and was a member of the circle around the Irish playwright and politician Richard Brinsley Sheridan.

In 1809, he went to Denmark to report on British military operations. His critical reporting led to him being deported back to London. Finnerty accused the powerful secretary of state for war, Lord Castleragh, of seeking to silence him, and also of having been responsible for the torture of United Irishmen prisoners in 1798. Castlereagh sued him and Finnerty was again imprisoned.

In the newly revealed Poetical Essay, Shelley attacks Castlereagh and denounces war as a time “When legal murders swell the lists of pride;/ When glory’s views the titled idiot guide”. He praises Finnerty’s supporters and asks rhetorically: “Shall rank corruption pass unheeded by,/Shall flattery’s voice ascend the wearied sky;/And shall no patriot tear the veil away/ Which hides these vices from the face of day?”

Shelley imagines Finnerty and his supports as “a powerful hand” stripping away “the guilt-stain’d veil” of corruption.

Shelley clearly intended his poem to be part of the wider campaign to raise funds for Finnerty, which also staged large public meetings in Dublin and Belfast. Finnerty was released in 1813 and returned to work as a journalist until his death in 1822. His friend William Hazlitt wrote of him that he “loved Ireland to the last, and would overwhelm any man with a torrent of [curses] who would speak disrespectfully of the sod.”

The poem is available online at poeticalessay.bodleian.ox.ac.uk.