A man whose mother, sister and aunt were shot and killed accused the policing minister of "pussy-footing around" by not bringing in a new law to ban people with a history of domestic violence from owning gun.
Damian Green has rejected Labour's calls for fresh legislation, telling the Commons that the Government would issue tough new guidelines to police forces on how they licensed firearms.
His stance was criticised by Labour, who evoked the case of taxi driver Michael Atherton, who shot dead his partner, her sister and her sister's daughter on New Year's Day last year in Horder, near Peterlee, County Durham.
Atherton then killed himself.
Atherton, 42, shot his partner Susan McGoldrick, 47, her sister Alison Turnbull, 44, and Ms Turnbull's daughter Tanya, 24, after a row at his home.
The weapon, a Hatson Escort Magnum semi-automatic shotgun, was one of six he was entitled to own despite a history of drunken domestic violence and an incident when he threatened to "blow his head off" in 2008.
On that occasion police removed his weapons but returned them a few weeks later with a warning to behave responsibly in future.
Alison Turnbull's son Bobby said: "Damian Green and the Home Office are pussy-footing around the subject because they do not want to upset Tory voters.
"It's a joke that they are sticking by changing the guidelines rather than changing the law.
"How long before the police are making sloppy decisions and they are again giving guns to pieces of dirt like Michael Atherton?"
In the Commons, Labour called on the Government to back its amendment to the Anti-Social Behaviour, Crime and Policing Bill which would change the law so that those who had a history of domestic violence could not own a gun.
Mr Green said he had spoken to Mr Turnbull, who works at Hartlepool golf course as a greenkeeper, and assured the Commons that the lessons of the case had been learned.
Grahame Morris, Labour MP for Easington, asked him: "Will the Home Secretary and you learn the lessons of history, not least the terrible tragedy of the Atherton case in my constituency and back the Labour amendment to the Anti-Social Behaviour, Crime and Policing Bill to make it clear in law to licensing officers that those with a history of domestic abuse, domestic violence should not be able to own a gun?"
Mr Green replied: "I'm happy to reassure you that we are learning the lessons of that terrible incident.
"Indeed, as you know, I've spoken to Bobby Turnbull on several occasions about this and I am happy to assure you that the strengthened guidance with the particular application to domestic violence will be introduced within a matter of weeks so that very direct lesson is being learnt very quickly."
But shadow home affairs minister David Hanson said guidance was not sufficient.
He said: "Bobby Turnbull's mother, sister and aunt were murdered on January 1 2012 by somebody who should not have had access to a firearm because of their history of domestic violence.
"Will you reflect on what you have just said now and accept that from this side of the House guidance on domestic violence and firearms is not sufficient?"
"Will you support the amendment we are putting forward on the Anti-Social Behaviour, Crime and Policing Bill this week or not?"
Mr Green replied: "As you know perfectly well we have already debated that amendment and as I say, we want to take practical steps to ensure that all police forces all over the country react appropriately to evidence of domestic violence when considering gun licensing and that's why we're strengthening the guidance and that's why we're going to do it very, very quickly."
The Bill is at committee stage in the Commons.
Mr Turnbull vowed to carry on fighting.
"It just makes me more determined," he said.
"I know for a fact I will get the law changed, it will just take us a bit longer."