A British magazine has published an image of a figure that it says is the first and only known demonstrably authentic portrait of William Shakespeare made in his lifetime.

The picture, of a young, bearded man wearing a Roman-style laurel crown and holding an ear of sweetcorn, was identified by botanist and historian Mark Griffiths and will be published in Country Life on Wednesday.

Until now, the only accepted authentic likenesses of Shakespeare, in which he is depicted as bald, have been found in the First Folio of his works and his monument at Holy Trinity Church, Stratford-upon-Avon, both created posthumously.