LONDON, England (AFP) – Prime Minister Tony Blair yesterday backed calls for tougher sentences for teenagers who carry guns and join criminal gangs after four people were murdered in London including three teenagers.

As a debate continued about how the teenage victims – two 15-year-old boys and a 16-year-old youth – came to be caught up in the violence, Blair said it was vital to curb the apparent rise in gun culture and young people joining gangs.

The fourth victim, a 28-year-old man, was shot dead on Saturday in the north of the city.

Blair and ministers are to assess proposals from London’s Metropolitan Police that include lowering the minimum age a person convicted of carrying an illegal weapon can be sentenced to five years in prison from 21 to 17.

But he denied claims from the leader of the main opposition Conservative Party, David Cameron, that the shootings symbolised a breakdown in British society, or that it was a “quick fix” solution to a complex social issue.

“It’s about a specific problem within a specific criminal culture to do with guns and gangs, which doesn’t make it any less serious, but I think it’s important, therefore, that we address that issue,” he told BBC television.

“How do we make sure that these groups of young people within these specific criminal cultures who are getting into gangs at an early age and using guns, how do we clamp down on it very hard and provide solutions?

“There is a particular problem which is that the minimum five-year sentence that we have introduced for illegal possession of a firearm does not apply to those under the age of 21 and we’ve got to lower that age… down to the age of 17.”

In the coming months, he said it will become a criminal offence to keep a gun or weapons for somebody else and agreed with police proposals to view gang membership as an aggravating factor in criminal activity, Blair said.

He also said anyone giving evidence against gang members in court should get greater protection and described as “sensible” proposals to increase surveillance on the homes of anyone suspected of using or trading in guns.

Meanwhile, the Metropolitan Police said a man was shot in the leg and injured in the Harlesden area of north-west London overnight, just 24 hours after a man was shot dead in Hackney, east London.

Three people – including two youths aged 18 and 19 – were also wounded in two separate shootings in inner-city Manchester, northwest England, overnight Friday-Saturday.

Despite the spate of shootings, crime involving weapons is still relatively rare on Britain’s streets and the majority of police are not armed.

But after the deaths of the two 15-year-olds and the 16-year-old youth in south London, armed patrols have been sent to known south London hotspots as part of a high-profile crackdown.

In 2005-06, the number of gun murders fell by more than a third from 78 to 50; there were 11,084 recorded firearms incidents in the same period, up 0.12 per cent on the previous 12 months, Home Office figures show.

More than half (54 per cent) of the recorded incidents took place in London, the English West Midlands area and Greater Manchester.

Community leaders in south London have warned against exaggerating the scale of the problem while the former head of the Youth Justice Board in England and Wales has questioned whether stiffer sentences will act as a deterrent.

Reasons suggested for the apparent rise in gun culture include family breakdown, the lack of positive male role models and poor educational achievement and prospects – particularly among black African-Caribbean boys.