During a visit to the area by Home Secretary Priti Patel, chief constable of Devon and Cornwall Police Shaun Sawyer was confronted by former MoD armed security guard Stewart Parfitt, 78.
He demanded: “Why did you give that bloke his gun back when he’s been a bloody lunatic for years?”
The Home Secretary declined to answer any questions put to her around gun control but local Labour MP Luke Pollard said the people of Plymouth deserve “clear answers” as to how Davison got a firearms licence.
Mr Pollard said: “I want to see answers to two very simple questions – why did this happen, and how did this happen?
“But more than that, I don’t want to see any other community, anywhere in Britain, going through what we have over the last couple of days.
“We’ve got an entire community grieving here, we’ve got families grieving. We’ve got a three-year-old killed. We need to have proper answers here.”
The Independent Office for Police Conduct is investigating the Devon and Cornwall force after a shotgun and firearms licence was handed back to Davison last month.
They were taken away in December following an allegation of assault but reportedly returned after Davison attended an anger management course.
Labour leader Sir Keir Starmer welcomed the investigation but said: “How on earth did he get a gun licence in the first place? What backup checks were done? I do think there are wider questions here and that could involve a review of the gun licensing laws because there are other questions here that urgently need to be addressed.”
Former chief crown prosecutor for the North West Nazir Afzal said Davison’s social media posts appeared to have been missed when restoring his gun licence.
He told BBC Breakfast yesterday: “There were all these social media posts talking about the violence he believed in or felt was necessary, how he felt about women. None of that seems to have been taken into account.”
He added if police were aware of the posts “they have even more questions to be answered”.
However, Mr Afzal said forces do not have the resources to properly investigate firearms licences. He said: “That might mean the due diligence, the level of attention they need to put into this kind of decision, isn’t taken.”
Nick Kelly, leader of Plymouth City Council, said the investigation should try to piece together exactly why the licence was suspended, taken away in the first place, and why it was deemed appropriate to give back.
He said: “My own view is, why do you need a gun in the first place?
“If there’s a very legitimate reason, well, I would not want to take guns away from everybody.
“We just need to review it, look at the facts in this specific case and hopefully if tighter legislation is required that will be forthcoming.”
But Sir Peter Fahy, former chief constable of Greater Manchester Police, said while questions need to be answered on why the gun was returned, firearm laws “on the whole” appear to work.
He said: “There are only about 30 murders a year which involve firearms, and they are ones which are illegally held largely and you would never get a certificate for.”