Media playback is unsupported on your device Media caption Theresa May said 'middle men supplying firearms' are as guilty as the people who use them.

A new offence of supplying a firearm will be introduced to tackle people who hire out weapons to gangs, Home Secretary Theresa May has said.

Ms May told the BBC those supplying guns were "as guilty" as those using them as the impact was just as deadly.

The maximum sentence for the offence, which will apply in England, Wales and Scotland, will be life imprisonment.

It is one of a number of measures to be outlined by David Cameron on Monday in a speech on crime.

Labour MP Keith Vaz, who chairs the cross-party Home Affairs Committee, welcomed the tougher sentences for "gun-running" but said the change must be made in consultation with the police.

The government is looking to regain the initiative after a difficult week dominated by the resignation of the Chief Whip, Andrew Mitchell.

'Rented guns'

No 10's handling of Mr Mitchell's departure, five weeks after a confrontation with a police officer outside Downing Street, has been questioned within the Conservative Party.

The prime minister has also been criticised for confusion over the government's energy policy and fresh accusations that senior ministers are out of touch with the public.

Analysis David Cameron's crime speech has been a long time in the writing. No 10 has hinted for months that the prime minister's first major address on law and order was just around the corner. Other things always seemed to get in the way. Perhaps that is why a lot of the measures that have been briefed to the papers seem quite familiar. We knew that payment by results for cutting reoffending was being extended. The new gun-running offence has been on the cards since earlier in the year. Therefore it's more interesting for what it tells us about the prime minister's instincts in this area. Gone are the very 2005-ish ideas of showing more love to young offenders. In, instead, is the very 2012-ish idea of being tough on crime. Britain's changing firearms laws

Monday's speech will be an attempt to end what he will characterise as a sterile debate between those who call for tougher sentencing and others who want to see more rehabilitation of offenders and say that "retribution isn't a dirty word".

Ahead of the speech, Mrs May confirmed that gun-runners who supply lethal weapons to gangsters could be given life sentences, telling the BBC's Sunday Politics show the actions of those individuals needed to be treated more seriously.

"We know there are middle men, who have firearms that they then rent out to criminals who then use them.

"There isn't at the moment an offence for someone to possess a firearm with the intent to supply it to someone else.

"I think it is right that we introduce that offence, because those people who are supplying the firearms are as guilty as the people using them when it comes to the impact."

'Strong message'

Since 1968, possessing firearms with intent to endanger life has carried a maximum sentence of life, but the police say it is hard to secure convictions in cases of trafficking by proving intent.

At the moment, people who deal in guns are mostly charged with separate offences under the Firearms Act, which carry sentences of up to 10 years, but ministers have been persuaded of the need for a specific new offence with a tougher penalty.

Welcoming the move, Mr Vaz said: "We have to make sure the law is very strong when people decide to sell firearms illegally or give firearms for other people to use illegally," he said. "This will send out a very strong message to those involved in criminal activity."

The Association of Chief Police Officers said it was vital that those who imported, sold and distributed weapons were "appropriately dealt with" and the penalties "reflected the damage" their actions did to families and communities.

However, a document produced by the Home Office earlier this year questioned the effectiveness of a new offence of possession with intent to traffic weapons.

EXISTING OFFENCES AND SENTENCES Sentences for offences involving prohibited firearms are covered by the 1968 Firearms Act

Possession of a firearm with intent to endanger life (maximum life sentence)

Possession with intent to cause fear of violence (maximum 10 years)

Illegally importing firearms or ammunition (maximum 10 years)

Unregistered selling, transfer or repair of a firearm (maximum five years)

Possession, purchase, sale or transfer of prohibited weapons and ammunition (maximum 10 years)

The document, produced as part of a consultation on the issue, said as many as 20 offenders could be affected each year.

It said evidence on whether it would reduce firearms offences by acting as a deterrent was "mixed". Any reduction in gun offences was likely to be temporary, it added, with the gap in the firearms market "likely to be filled by other individuals".

On Monday, the prime minister is also expected to announce that a payment by results system for private companies will be expanded and the practice of giving all prisoners £46 in cash when they are released from prison may be ended.

Labour say that, far from being tough on crime, the government was cutting 15,000 police officers, curbing the use of CCTV cameras and "watering down" regulations on the use of DNA in criminal investigations.

The speech comes after the prime minister replaced Ken Clarke with Chris Grayling as justice secretary in September's reshuffle, a move widely interpreted as a shift to the right.

Mr Grayling has already announced plans to toughen community sentences and give householders who react with force when confronted by burglars more legal protection.