Sinn Fein's £1.5m mystery donor William E Hampton had schizoaffective disorder
The reclusive English millionaire who left the vast majority of his fortune to Sinn Fein was suffering from schizoaffective disorder at the time of his death.
William E Hampton's death certificate revealed the elderly English man had a condition which can cause delusions, hallucinations and depression before he died.
Mr Hampton, who left £1.5m to Sinn Fein, died aged 82 in a nursing home in Wales in January 2018.
His death certificate showed he died of respiratory failures and end stage chronic pulmonary disease. It also notes that he was "frail" and had "schizoaffective disorder" at the time.
It has been reported that Mr Hampton had mental health issues and may have even mutilated himself.
Mr Hampton's donation to Sinn Fein emerged after Northern Ireland introduced strict new rules on political funding.
His will showed that he left an estate of almost £2.6m.
The will, which was made in June 1997, shows that Mr Hampton decided to make Sinn Fein's national treasurers, Dessie Mackin and Joe Cahill, the executors and trustees.
Their address is listed as 44 Parnell Square, which is the party's headquarters in Dublin.
Mr Cahill, who has since died, was a senior figure in the Provisional IRA and Mr Mackin has a conviction for IRA membership.
Mr Hampton left several sums of £1,000 to various people in his will, including British Labour MP Dennis Skinner and Private Eye investigative journalist Paul Halloran.
However, the will states: "All the rest, residue and remainder of my estate of whatsoever nature and whatsoever situate, to include my assets in Ireland, England, Singapore and New Zealand and other assets I may have anywhere else in the world, I give, devise and bequeath to my executors and trustees... the political party in the Republic of Ireland known at this time as Sinn Fein."
The donation was intended to "cover election expenses, to fund Sinn Fein offices and advice centres and to aid republican prisoners and their families in both Ireland and Britain".
Mr Hampton said that if Sinn Fein was no longer in existence at the time of his death, the money should go to "the political party to which Mr Gerry Adams, MP, then belongs".
And, if Mr Adams was already dead or no longer a member of a political party, the money was to go to "the republican or nationalist party in the six counties other than the SDLP which has the largest number of elected local councillors".
Mr Hampton also left £5,000 to Rosalind Morton who he reportedly met after he was admitted to a psychiatric unit when he physically harmed himself. British newspaper The Times reported that he sliced off his own penis after being accused of having an affair with another man's wife.
Ms Morton said Mr Hampton was a "lovely man" but he had some "issues". She said she would irregularly hear from her friend who would travel the world in his camper van.
Mr Hampton is known to have spent extended periods of time living in his camper van in Ireland. He lived in West Cork in the 1980s and bought a property in a townland near Bantry.
"He would go off on his own in his caravan and come back once or twice a year to tell us about his adventures. He would go to Thailand and sleep on the streets," Ms Morton said.
In letters and postcards sent to Ms Morton, Mr Hampton would criticise the British government.
One letter read: "It was England that kicked me into the hands of Sinn Fein by 15 years of acts of terrorism, fraud, lies and deceits too numerous to mention."
In his home town of Fenstanton, in Cambridgeshire, his neighbours said they were surprised Mr Hampton left his family's fortune to Sinn Fein as he had never mentioned supporting the party while living in the area.
Asked about his well-being before his death, Sinn Fein leader Mary Lou McDonald said it would be "inappropriate" to discuss the mental health of someone who is believed to be the largest single donor to the party's financial coffers.
Ms McDonald said the money was donated to Sinn Fein "within all of the rules and regulations and will be spent within the rules and regulations".
"I did not know Billy Hampton but judging from people who did know him he considered this to be a very robust statement against the political establishment," she added.
"He obviously saw in Sinn Fein an organisation that is full square for Irish unity, for progress and for peace and prosperity in Ireland but also a party that stands full square against the political establishment.
"I can only say Billy was a rebel, a rebel with a cause. He clearly shared our goals."