Arafat fell ill in October 2004, displaying symptoms of acute gastroenteritis with diarrhoea and vomiting. At first Palestinian officials said he was suffering from influenza.
He was flown to Paris in a French government plane but fell into a coma shortly after his arrival at the Percy military hospital in the suburb of Clamart, where he died on 11th November.
The official cause of death was a massive stroke but French doctors said at the time they were unable to determine the origin of his illness and no autopsy was carried out.
Polonium- 210 was responsible for the death of defecting Russian spy Alexander Litvinenko in 2006 after it was slipped into a cup of tea in a London hotel. From his deathbed, Litvinenko accused Russian President Vladimir Putin of ordering his murder.
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The suspect, 35-year-old Willie Corey Godbolt, has been arrested and was being treated for a gunshot wound in hospital.
Mohanna Abdhou, known as Montana, was out with friends when two attackers cycled up to them and opened fire in Brent, north-west London.
The US president tweeted that Mrs May gave him "full details" of the incident during talks while he attended summits in Europe.