The New Year's Day shootings in Peterlee, County Durham, have reopened the debate about whether Britain's firearms laws should be tightened further, after it emerged the man behind the killings had a licence for six weapons.

Taxi driver Michael Atherton - who shot dead his partner and two other women before killing himself on Sunday - had licences for three shotguns and three "Section One" firearms such as rifles.

Atherton reportedly threatened to commit suicide in 2008, and friends have since said that they believed the taxi driver was depressed before he opened fire on his partner, her daughter and her sister.

Under current laws, owners of shotguns and rifles must undergo background checks which are supposed to ensure they pose no threat to public safety.

People applying for permission to keep a gun must declare any criminal records and relevant medical conditions, including any previous treatment for depression or mental illness.

Police forces have powers to revoke firearms licences if officers receive information about new convictions or changes in the certificate-holder's mental health.

But a series of horrifying mass shootings over the years - in particular in Hungerford in August 1987, Dunblane in March 1996 and Cumbria in June 2010 - have raised questions about whether enough is done to stop guns legally ending up in the hands of dangerously unstable people.

Speaking to the BBC's Today programme, Roger Gray, a former firearms tactical adviser to the Metropolitan police, said the current framework was "sufficient" but the level of scrutiny needed to be addressed.

"I would feel that if someone started to present themselves as a self harmer, or as a danger to themselves or others, the possibility of a firearm should be scrutinised to the nth degree and perhaps the firearm should be taken away

"I think the framework of law is sufficient, it is the application of that framework which needs to be looked at.

"We need to put more pressure and make more resources available to literally police the ownership of firearms to a greater extent.

"The level of scrutiny, I would say, needs to go up, and this one has definitely slipped through the net."

Number 10 said that there will be be no review of firearms legislation, stating: "Our laws are already among toughest in the world"

Prime Minister David Cameron said the government was "trying to balance the need to protect public safety with the need to make sure those controls are practical and work.

"On this specific case we need to wait for the investigation to conclude."

Ministers were looking at guidance and the way gun laws were implemented following a critical report by the Home Affairs Select Committee, he said.

Both types of firearms certification are reviewed every five years, although fewer than 1% of applications to renew a shotgun licence were rejected in 2009-10.

Home Office figures for England and Wales show there were 141,775 certificates on issue for Section One firearms and 580,653 for shotguns at the end of March 2010.

Police revoked 302 firearms licences and 1,076 shotgun licences in 2009-10.

The British Association for Shooting and Conservation (BASC) have called for the "facts" in the case to be looked at before drawing any conclusions.

"There has just been a comprehensive parliamentary review of firearms law in the UK and the facts in this incident need to be firmly established."

David Taylor, Shooting Campaign Manager for the Countryside Alliance, said he welcomed the government's response on the issue.

"The laws that govern shooting have been carefully drawn and added-to over several years so that today they are as rigorous and all-encompassing as possible.

"There looks to have been a failure at some point in the process in this event, and the most sensible action is to investigate what went wrong and then decide how it might be fixed.”

In December 2010, the Commons Home Affairs Select Committee described legislation in England and Wales as a "complex and confused" mess and called for tighter restrictions on gun licences.

The MPs called for convicted criminals who receive suspended jail terms - like taxi driver Derrick Bird, who ended up killing 12 people in the 2010 Cumbria shooting spree - to be stripped of firearms licences to prevent future incidents.

Shooting organisations stress that the UK's gun laws are already extremely tough and have warned against a "knee-jerk" reaction to the latest tragedy.

Stressing that the vast majority of gun-related homicide and crime involved illegally-held firearms, Shooting Sports Trust spokesman Mike Yardley said said any applicant for a shotgun certificate must undergo thorough background checks and prove they represent now danger to public safety..

"The applicant must provide GP details, a referee - two for a firearms certificate for section 1 firearms such as rifles - and show that he or she has somewhere safe to store a shotgun.

"No licensing system can be perfect, but it would be hard to see how the present system could be much improved," he was quoted by the Press Association as saying.

"We have very tough gun laws in the United Kingdom and we also have a very small amount of gun crime."

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