Eight years ago a previously unknown poem, 'Shall I die', found in the Bodleian Library in Oxford, was authenticated by computer and included in the latest Oxford University Press complete works of the bard.
Now Charles Hamilton, 79, a New York handwriting expert and veteran of more than 100 court cases, claims he has found the original manuscript for Cardenio, a joint work by Shakespeare and his protege John Fletcher in 1612.
Based on the story of Don Quixote, published in English earlier that year, and known from court records to have been performed at least twice, it has been lost for at least 200 years. Mr Hamilton created a stir in 1986 by claiming in defiance of the universal academic opinion, then and now, that the handwriting of Shakespeare's will was the bard's own, not that of his solicitor, Francis Collins.
Now he is convinced, '99 per cent . . . enough to testify in court', that the manuscript of a play from 1612 in the British Library, known as The Second Maiden's Tragedy and attributed to Thomas Middleton, is in the same handwriting as Shakespeare's will, and must, therefore, be the lost Cardenio.
'I was fortunate enough to come across a facsimile in the rare book room of the New York public library, while I was going through a pile of old stuff,' he said.
Dr Martin Wiggins, fellow of the Shakespeare Institute in Stratford- upon-Avon, who is editing The Second Maiden's Tragedy for a new Oxford University Press edition, is deeply sceptical: 'Its plot is of a tyrant's sexual obsession with a lady. He pursues her, and she
is so chaste she commits suicide. He proceeds to dig her up and crown her his queen, and indulge in a spot of necrophilia. That is not the story of Cardenio.'
But academics should beware. Mr Hamilton was way ahead of them in spotting that the Hitler diaries were fake.