SHAKESPEARE scholarship, lively at the best of times, saw the fur flying yesterday after a German academic claimed to have authenticated not just one but four contemporary images of the playwright - and suggested, to boot, that he had died of cancer.

As the National Portrait Gallery planned to reveal that only one of half a dozen claimed portraits of William Shakespeare can now be considered genuine, Prof Hildegard Hammerschmidt-Hummel said she could prove that there were at least four surviving portraits of the playwright.

Startlingly, she said swellings close to Shakespeare's left eye, which she says are clear in several of the contested portraits, are evidence that he had lymph cancer. By dating the portraits, she said, it was likely that he had suffered for around 15 years in increasing pain and died from it.

Little is certain in Shakespeare studies - nothing is known about his death in 1616 and much of his life is a mystery - but if Prof Hammerschmidt-Hummel's claims win backing they will throw the National Portrait Gallery's three-year research project into the authenticity of Shakespeare portraits into serious doubt.

But the first reaction to her claims in Britain was not positive. Stanley Wells, Emeritus Professor of Shakespeare Studies at Birmingham University, called the German's findings "rubbish''. And the portrait gallery claimed that Prof Hammerschmidt-Hummel's work was based on a "fundamental misunderstanding''.

Prof Hammerschmidt-Hummel, who teaches English literature and culture at Marburg and Mainz University, took the unusual step of using forensic tests used by German detectives to study the morphology of paintings and sculptures that are claimed to be of Shakespeare.

Measuring facial features - nose, eyes, lips, chin etc - and the relationships between them she claims that two paintings, a bust and a contested death mask of the playwright show identical characteristics.

The features are so similar, she claims, that they must be the result of sittings with Shakespeare himself.

The four images with the morphological similarities are, she reveals in a book to be published in Britain in April, the Flower Shakespeare, named after the brewery family that gave the picture to the Royal Shakespeare Company in 1895, the Chandos Shakespeare, presented to the nation by Lord Ellesmere in 1856, the terracotta Davenant Bust, which stands in the Garrick Club in London, and the Darmstadt Death Mask.

So-called because it resides in Darmstadt Castle in Germany, the mask is dismissed by many as a 19th century fake but Prof Hammerschmidt-Hummel says that the features, and most notably the impression of a swelling above the left-eye make it certain that it was taken within days of Shakespeare's death. She said: "The cancerous growths grow bigger as the dates progress.

''Everybody else has missed them but how else would an artist know they were there unless they had seen Shakespeare.''

Research for the book has taken 10 years and she says pathologists, doctors, ophthalmologists, dermatologists and imaging engineers have helped her build 3D images to demonstrate the similarities. The professor, who has previously claimed that Princes William and Harry are directly descended from Shakespeare, will have trouble persuading doubters over at least two of the images, however. Research by the NPG last year found that the Flower Shakespeare was a 19th century fake using pigment not in use until around 1818. And the Davenant Bust has long been attributed to the 18th century French sculptor Louis Francois Roubiliac.

Prof Hammerschmidt-Hummel says the bust was mistakenly attributed. As to the Flower Shakespeare, she risks even more controversy. She claims the picture in the RSC's collection and rejected by the NPG must be a fake or a copy of the picture that she tested in 1996.

The NPG's own research into six possible contemporary portraits of the playwright has concluded that only one, the Chandos Shakespeare, is a likely candidate. All six considered will be displayed for the first time together in an exhibition at the gallery opening next week.

Prof Hammerschmidt-Hummel told The Daily Telegraph: "I am absolutely certain of my findings. I dispute the evidence of the portrait gallery and Stanley Wells is not an art historian.'' Dr Tarnya Cooper, in charge of the NPG's research, said: "My view about using measurements of facial features from portraiture is that this is based on a fundamental misunderstanding about the nature of visual art. Portraits are not, and can never be forensic evidence of likeness.''

A life and death shrouded in mystery

SHAKESPEARE'S lymph cancer would have caused a slow and eventually painful death and it could be an explanation for the playwright's decision to stop writing and leave London for Stratford-upon-Avon three years before he died in 1616. But so could many other things.

"Yes, I have heard that one [cancer] before. I don't believe it. We simply have no idea how or why he died or can even be certain where he died,'' says Prof Stanley Wells, one of the country's top Shakespeare scholars.

Plausibly, syphilis and typhoid have also been put forward as causes of death. It has also been suggested that the playwright caught a fever after a particularly drunken night on the tiles with Ben Jonson and another story is that he was poisoned by his son-in-law John Hall.

Prof Wells believes that this is the easiest to rule out. "Hall was a very distinguished physician. I think that one is pure fantasy.''

Hall treated many people in and around Stratford, keeping notes of his consultations. The pity is that no notebook has been found for the period in which he might have treated his father-in-law.

Recently, a group of American academics suggested digging up Shakespeare's tomb inside Holy Trinity, Stratford, to take DNA samples. Prof Wells is not opposed to this, though he thinks that it is by no means certain that the bones of the playwright will be found beneath the gravestone near the chancel