Conn O’Neill took the step following a row over Mr Blackford’s treatment of the late Lib Dem leader when he beat him for the Ross, Skye and Lochaber seat.
Mr O’Neill passed the document to The Scotsman after Mr Blackford said he was proud of the way the SNP had conducted the campaign.
Controversy over Mr Blackford’s behaviour has raged ever since Mr Kennedy died just a few weeks after losing his seat having fought a long battle against alcoholism. Friends of Mr Kennedy have accused Mr Blackford of leading a campaign that unleashed a torrent of abuse against the Lib Dem and which mocked his battle with the bottle.
In a weekend interview, Mr Blackford was asked about a now notorious incident when he marched angrily into Mr Kennedy’s office during the election campaign and demanded that the Lib Dems remove a description of him as a “well-funded banker” from their campaign literature.
Mr Blackford, a former senior executive at Deutsche Bank, said he had asked Mr Kennedy to “lay off” the personal attack on him and his staff had brought the Lib Dems cakes on another occasion.
Angered by Mr Blackford’s version of the incident, Mr O’Neill produced the note he wrote to police at the time.
The note said Mr Blackford and four supporters – three male and one female – came to Mr Kennedy’s Fort William Office at 10am on 15 April, a few weeks before polling day. “Mr Blackford was angry, aggressive and unpleasant in his manner towards the three of us in the office,” Mr O’Neill’s note said.
“He was wagging his finger in my face and had stepped very determinedly into my personal space. In a raised voice, he demanded an apology for and retraction of the Facebook post which had described him as a banker. He said we were making a slur against him and had made this campaign dirty before telling me ‘you’ll deserve all you get’. After several minutes of him shouting at me, I told Mr Blackford that no apology would be forthcoming and thanked him for visiting, he turned to leave with the men who had accompanied him.
“The woman who had come in with him stayed for a further five minutes questioning why we felt justified in describing Mr Blackford as a banker from Edinburgh. This is the fourth time Mr Blackford has come into the office, when he has visited he has caused members of staff to feel uncomfortable and intimidated.”
The note was clear that Mr O’Neill did not want to see any formal police action at that stage, but it added that it had been logged with officers “in case there are further incidents”. Yesterday he added that Mr Blackford was “directly hostile” towards him in Mr Kennedy’s office. He said that SNP activists came to the office with cupcakes a week later. “I can tell you that we binned them for fear they were poisoned, such was the atmosphere in that campaign,” Mr O’Neill said.
In a weekend interview in the Times, Mr Blackford was asked about the 2015 election. He said he was “proud” of the way the SNP conducted the campaign and said he respected Mr Kennedy as an outstanding parliamentarian.
He claimed to have no regrets when Mr Kennedy died claiming there was “absolutely no issue” between the Lib Dem and himself. He went on to say the Lib Dems ran a “nasty” campaign against him, which he did not blame Mr Kennedy for.
Yesterday the former Labour MP Brian Wilson accused Mr Blackford of an “odious attempt to re-write history” by playing down claims that he led a vendetta against the Lib Dem.
Mr Blackford was unavailable for comment yesterday. But an SNP source said the police had not made contact with him or his campaign team. The source added: “The campaign did not make personal attacks – questioning an MP’s absences from Parliament over a 15-year period is wholly legitimate.”
Police Scotland said it received a report of a minor disturbance on the date of the incident but no offences were committed.