Teenagers as young as 16 could be locked up if they are caught carrying a knife in public.

As fears grow over youngsters carrying blades, Gordon Brown is urging prosecutors to take many more 16 and 17-year-olds to court for knife crime.

The Prime Minister is calling for fewer cautions to be dished out by police and the Crown Prosecution Service (CPS) - at the moment, anyone under 18 caught with a knife gets a caution.

At a breakfast meeting with the CPS, police chiefs and other ministers to discuss the issue, the Director of Public Prosecutions, Sir Ken Macdonald QC, told Mr Brown: "When people come to us their expectation is a prosecution will follow.

"What we are proposing is that if people are carrying a knife and are prosecuted for other offences, they will be prosecuted for the knife too. We have set out some further guidance that the public interest is in favour of prosecution.

"It has become fashionable (to carry a knife). What we want people to understand is they put themselves at risk carrying these sorts of weapons."

An announcement by the CPS is expected shortly.

After the meeting, the Prime Minister said: "Carrying a knife is completely unacceptable. When any young person or teenager who is encouraged to carry a knife is not making themselves safer, they are all making it more likely crimes are committed.

"We have got to make sure if a young person is carrying a knife, there is a message they will end up in court.

"They are putting other children and young people at risk."

Also at the meeting were Home Secretary Jacqui Smith, Justice Secretary Jack Straw, Attorney-General Baroness Scotland and Sussex chief constable Ken Jones, who is the president of the Association of Chief Police Officers.

On Wednesday, Mr Brown told the House of Commons that parents also needed to be responsible for telling their children not to carry knives.

He told MPs: "Every parent will want their teenage sons and daughters not only to be safe but to feel safe in our neighbourhoods.

"That's why knives are unacceptable and we've got to do everything in our power to deter them."

On Tuesday, Ms Smith outlined measures to tackle knife crime, including an advertising campaign aimed at deterring young people from carrying knives. She said information would be provided to help parents broach the subject.

Last week, Metropolitan Police Commissioner Sir Ian Blair pledged to continue a controversial crackdown which has seen police in London using section 60 powers to stop and search people even if they have no suspicion that they are carrying a knife.

Critics have said that continued use of the powers could aggravate police relations with the community.

Sir Ian said the crackdown, called Operation Blunt, will stop when murders reduce.

Sixteen teenagers have been killed so far this year in the capital.

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