Yasser Arafat's widow is claiming her husband was the victim of a political assassination.

New evidence from Swiss scientists, obtained by television channel al-Jazeera, suggests the former Palestinian leader was poisoned with radioactive polonium.

Arafat (75) died in 2004, but his body was exhumed a year ago for tests, after it was alleged he had been murdered.

Rumours that Arafat might have been poisoned have circulated since his death, but there has never been any evidence before.

Journalist and Middle East expert Robert Fisk says he was already a very sick man in the period shortly before his death. According to Fisk, one anecdote from a diplomat who dealt with Arafat while he was under siege from the Israelis in his Ramallah compound suggested he had developed a habit of not wearing socks and of picking off the skin on his feet during meetings.

Robert Fisk thinks it is unlikely that the French authorities would have missed such an obvious case of poisoning:

One British diplomat says the type of polonium could only have come from a nuclear reactor - only a small group of people, including Israel, would have had access to polonium.

But scientists who examined Arafat's body didn't find any puncture wounds, meaning the polonium would probably have to have been administered in food or liquid form.