Derrick Bird held a firearms licence for 20 years before he embarked on his killing spree.

The taxi driver had a shotgun certificate and a firearms licence for weapons. He is understood to have been a licensed firearms holder since the age of 32.

Under British law, those wishing to acquire a gun must complete applications and interviews with the police or firearms licensing authority before they acquire a weapon.

The country's firearms licensing system is among the toughest in the world and licence holders have to provide reports from their doctor, disclose any criminal convictions and state why they want a gun.

It takes eight weeks on average to complete the process.

But despite the length of the procedure, nearly 600,000 people in the UK legally own a shotgun and just over 100,000 own a firearm.

A shotgun is defined by its smooth bore and fires cartridges or blanks, while a firearm has a rifled barrel and fires bullets.

Firearms expert Michael Yardley, spokesman for the Shooting Sports Trust, described the process of acquiring a shotgun or firearm as "complicated".

He said: "You have to apply to the police by filling out a form. You have to declare criminal convictions.

"You have to provide details of your GP and his or her address and police will follow that up.

"The police will come and see your security measures - for example, that you have a gun cabinet."

Mr Yardley, who gave evidence to the inquiry into the Dunblane school shootings in 1996, added: "The majority of legal gun owners are responsible and use their weapon for sport and hunting."

The Cumbria shootings, he suggested, had all the hallmarks of so-called "amok killings" - when the killer has snapped and embarked on a random spree.

Gun enthusiasts expressed dismay and shock at the killings, but were quick to defend the UK's licensing laws.

British Association for Shooting and Conservation spokesman Simon Clarke said: "The events... in Cumbria are tragic and shocking and as representatives of Britain's lawful gun owners, BASC would like to make clear its deeply-felt sorrow at these events, which will have long-lasting repercussions within the affected families and communities.

"Britain's firearms licensing system is among the toughest in the world and includes numerous safety and medical checks and balances.

"The UK has a well-worked approach to draw all possible lessons from any such event and we will cooperate fully where our expertise is appropriate."

One anti-gun violence campaign group said the events illustrated the danger of assuming firearms are safe in the hands of seemingly normal people.

The International Action Network on Small Arms said the majority of high-profile mass shootings around the world had been perpetrated by licensed gun-holders using licensed weapons.

Director Rebecca Peters said: "The idea that only 'bad guys' do things like this is false.

"People who are not career criminals can turn violent. Having weapons designed to kill people is dangerous.

"The gun lobby says legal gun holders are not a problem at all and what we have to worry about is career criminals.

How events unfolded on day of horror

10.35 a.m. - Emergency services are called to Duke Street in Whitehaven after shots are fired. Shortly afterwards, officers urge people living in Whitehaven, Egremont and Seascale to stay indoors.

12.18 p.m. - Police confirm "a number of people" have been injured in a series of shootings.

12.41p.m. - Officers name the suspect as Derrick Bird, 52, from Rowrah, near Frizington, and issue a photograph of him.

1.04 p.m. - Radio Cumbria reports that at least four people are feared dead as police reveal that Bird has abandoned his car near Boot and is now believed to be on foot.

1.40 p.m. - The body of Mr Bird is found in a wooded area near Boot.

5.25 p.m. - Deputy Chief Constable Stuart Hyde says 12 people were killed by Mr Bird and a further 25 were injured. He adds that officers are investigating at 30 separate crime scenes.

8.20 p.m. - The Queen releases a statement saying she was "deeply shocked" by the shootings in Cumbria and shared the country's "grief and horror".