Prison staff warned that the former GP spoke of his intention to take his own life after his wife's financial security was assured, the report by the Prison Service Ombudsman said.
Stephen Shaw praised the efforts of staff at Frankland Prison in Durham to monitor Shipman, but criticised the failure to pass on information when he was transferred to Wakefield Prison where the former GP hanged himself four years into a sentence of 15 life terms. At Frankland, Shipman was put on suicide watch several times, and staff made "numerous" references to suicide on his file.
In March 2001 the killer wrote in his diary: "... I'm looking at dying, the only question is when and can I hide it from everyone?" In January 2001 he wrote: "My wife and the kids have to go on without me when it is the right time. Got to keep the façade intact for the time being."
Staff at Frankland concluded that Shipman would not give clues if he decided to take his own life. The report said: "The report of the case conference added (probably quite presciently): 'It was generally felt by all at the case conference that if [the man] had decided to take his life it would be 'calculated', he would 'lull staff into a false sense of security', showing no signs of depression or self-harm ... in fact, he would probably give the impression of being quite settled, jovial in mood and planning activities for the future.'"
Shipman, who is thought to have killed 250 people, was found dead in his cell at 6am on 13 January last year, the day before his 58th birthday.
Yesterday, friends of Shipman's victims expressed dismay that he had been allowed to take his own life, but Mr Shaw's report said staff could not have predicted the timing of his suicide. The report insisted it could not have been predicted or prevented.
But the report added: "I am critical of the fact that staff at Wakefield do not appear to have been alerted to the man's long-term risk of suicide or what might finally trigger it."
Mr Shaw said: "There is a wealth of information buried in his records about the connection between his pension, his appeal against conviction and his possible suicide, [and] none of this appears to have been flagged up for either wing staff or staff in the correspondence office at Wakefield."
His report said prison authorities needed to review procedures for at-risk prisoners and criticised as "harsh" the decision to withdraw some of Shipman's prison privileges in the weeks before his death.
Staff had downgraded Shipman to "basic" privileges, cutting his cash for phone calls and shortening family visits, despite the murderer being polite, tidy and obeying prison rules.
Mr Shaw's report made 17 recommendations, criticising poor record-keeping at Wakefield which meant he could not establish the precise time of events leading up to Shipman's death.
He also said it was "extremely regrettable" that the jail had the wrong details for Shipman's family and that his wife, Primrose, learnt about his death from a family member who heard it on the radio.
The Home Office said it accepted the recommendations, and said many had already been implemented.
'There is no possible way I can carry on'
13 January 2001: "So depressed. If [illegible] says no then that is it. There is no possible way I can carry on."
14 January 2001 (Shipman's 55th birthday): "[My wife] and the kids have to go on without me when it is the right time. Got to keep the façade intact for the time being."
27 March 2001: "I'm looking at dying, the only question is when and can I hide it from everyone?"
13 April 2001 (Good Friday): "If I was dead they'd stop being in limbo and get on with their life perhaps. I'll think a bit more about it. I'm desperate, no one to talk about it to who I can trust. Everyone will talk to the POs [prison officers] then I'll be watched 24hrs a day and I don't want that."
26 June 2001: "As near suicide as can be, know how and when, just not yet."
14 January 2002: "56 today, cards from everyone - very very sad day, not what life is about at all. [ ] not very good, it must be dreadful for her."
17 October 2002: "No money. [Wife] not able to get DHSS to see the poverty she is in. Only the kids who have been absolutely brilliant."
7 January 2003: "If this year doesn't get anywhere I know it is not worth the effort. I have to lock down this overwhelming emotion or else I'd be on a suicide watch or drugs."