Dr John Crichton, who was the main Crown psychiatrist at the trial of triple child-killer Theresa Riggi, believes making it harder to buy the most common of all murder weapons will help prevent knife killings.
He said knives with blunt tips would be equally effective for cooking but less likely to become weapons.
Dr Crichton, an honorary fellow at Edinburgh University's school of law, said Riggi, who murdered her children in August 2010, had planned to gas the youngsters but chose an easier option, and killed them with ordinary kitchen knives. He said the case made him think of research showing suicides fell in the UK after changes such as having natural gas instead of more lethal coal gas in cookers.
"If you make it more difficult then the rate reduces," said Dr Crichton. "What that shows us is people who are suicidal are ambivalent. They are quite impulsive in what they are doing and if you put barriers in people's way then they think again.
"The suggestion is that something similar goes on in terms of homicide perhaps."
David Sinclair, spokesman for Victim Support Scotland, said: "We would certainly be happy to see anything which helped make that type of weapon safer."