Serial killer Harold Shipman was so 'cold and calculating' that he even planned his own death to ensure his wife would receive a £100,000 pension payout.
Shipman, who was dubbed 'Dr Death' for the murder of 15 victims over a 23-year period, plotted to end his life either by suicide or by provoking another inmate into killing him once his GP pension had matured, according to prison files published for the first time.
His eventual suicide on January 13, 2004, guaranteed his wife, Primrose, would receive the lump sum, plus £10,000 for every year thereafter.
Had he waited until his 60th birthday, she would not have received the £100,000 and her annual income would be reduced to £5,000.
Other files which have been shown to MailOnline include Shipman's psychology report and life sentence plans.
They reveal that Shipman made threats to other prisoners and told one: 'Remember, I'm a doctor and I know where to cut you.'
He refused to co-operate with prison programmes and only gave one 90-minute interview about his crimes.
A report produced just three months before his suicide suggested Shipman, who worked from a practise in Hyde, Greater Manchester, had shown 'no reduction of risk and remains a high risk of re-offending'.
To support this, another document shows how Shipman honed in on sick, elderly prisoners - one he is said to have befriended claimed to have won the lottery.
The files state: 'Recent security information indicates Mr Shipman has forged a friendship with inmate (blanked out) who claims to have won the lottery and hence has a substantial sum of money.
'(Blanked out) is an elderly inmate who has significant medical problems and Mr Shipman has been giving him medical advice.
'Therefore the police who interviewed inmate (blanked out) considers him at risk from Mr Shipman,..
'Under no circumstances should Mr Shipman be allowed access to elderly or infirm inmates or be in a position to give medical treatment, as this is extremely risky as it may possibly act as a trigger for further offending behaviour whilst in custody.'
The shocking documents - which are available to view by the public - were uncovered by Dr Tom Clark, a lecturer at Sheffield University specialising in sociology and serial killers.
Although meant to remain sealed until 2069, a copy was found in the public records office at Kew while researching for his new book, The Sociology of Evil.
Prof Clark said: 'I was looking at files on Myra Hindley when I found that Shipman's files were also available.
'They reveal just how cold and calculating Shipman was. He was as cold and calculating with his own life, just as much as with others.