Literary biographers almost invariably conclude that their subject is unjustly neglected and deserves to be more widely read. Few writers have a reputation as uninspiring as Edmund Spenser (1554?-99), a poet who commands hardly any general readers and who English undergraduates routinely shun. Tom Paulin described his magnum opus, The Faerie Queene as "mercifully unfinished"; Philip Larkin went further, writing in his Oxford College's library copy, "First I thought that Troilus and Criseyde was the most boring poem in English. Then I thought Beowulf was. Then I thought Paradise Lost was. Now I know that The Faerie Queene is the dullest thing out. Blast it.'

As if that was not enough, Spenser acquired a reasonable fortune as a colonist in Ireland where he lived for the last 20 years of his life, and recommended that many of the rebellious natives be slaughtered. For the radical playwright John Arden, Spenser was an advocate of 'genocide', a forerunner of a number of 20th-century ideologues; the central postcolonial figure Edward Said complained that literary historians failed to 'connect his bloodthirsty plans for Ireland, where he imagined a British army virtually exterminating the native inhabitants, with his poetic achievement.'

I have just written a biography of Spenser and the troubling aspect of these two judgements is that they are half-right. Spenser is not a boring writer, certainly not "Elizabeth's arse-kissing poet", as Karl Marx rather rudely called him, and his work is notable mainly for its ceaseless experimentalism. Ezra Pound demanded that a true writer had to 'make it new' and no one in English literary history made more things new than Spenser. He invented his own stanza; his own styles of poetic language; the romance-epic, a weird combination of English, Italian and Classical poetry; wrote strange and misleading commentaries to his poetry; and was the first poet to write a marriage hymn about his own wedding.

He made it clear that he valued his own wife above the queen and was relentlessly disrespectful to the good and the great in his poetry, eventually provoking King James VI of Scotland (the future James I of England) into demanding that he be punished for representing James mother, Mary Queen of Scots, as the Whore of Babylon. And he is surely the only poet who imagined the queen looking through his bedroom window on his wedding night, asking the monarch to help lead his 'timely seed' into his wife's 'chaste womb'; or who thought that the Apocalyptic battle for the future of mankind would take place on a hill near his house.

However, like Ezra Pound, Spenser wrote many appalling things. He did indeed recommend that the Irish be starved into submission and slaughtered en masse if they refused to surrender to the conquering English crown forces. Although undoubtedly inspired by the fear of losing his estate, Spenser's judgement that the Irish who crept out of the woods eating dead bodies out of graves because there was nothing left in the barren landscape deserved their fate still has the power to shock.

Indeed, that is part of - if not the main - problem. Spenser loves to goad, prod and torment his readers, trying to force them to accept that the things they find most horrifying may well be true and necessary. He does not defend the brutal policies of the English in Ireland, he puts them on display, making us imagine that we are there with him, witnessing the carnage in Ireland and, in the end, supporting actions more terrible than we had ever imagined possible. It is not Spenser who has disguised his colonial attitudes; it is generations of critics and readers who have done that on his behalf, in the process, rendering him anodyne, toothless and irrelevant.

Needless to say Spenser is not an easy poet to like without qualification. But he is central to the English poetic tradition and sidelining his achievements makes English literature more watery and bloodless. We care about Shakespeare, Marlowe, Sidney, Raleigh and a host of politicians such as Lord Burghley and Sir Francis Walsingham, all larger-than-life characters who we imagine made the Elizabethan world what it was.

Spenser is excluded from this list because there has not been a biography of him since the 1940s and he is seen as a shadowy, obscure and dull figure. Yet when he died a host of poets recognised him as the greatest writer of their age, throwing poems and quills into his grave in Westminster Abbey. Many people visit Poets' Corner in Westminster Abbey, however they probably miss the monument to Spenser, tucked away in a corner. But it was his tomb that established the tradition of burying the nation's poets as a cluster. We would do well to remember his importance as a writer and a poetic thinker who did so much to make English literature what it is.

Andrew Hadfield's new book, Edmund Spenser: A Life (published by Oxford University Press) is available now, priced £25.00.