Murderers who kill with a knife will spend a minimum of 25 years in prison under proposals announced by Jack Straw yesterday.

The Justice Secretary outlined the plans after controversy over the sentences given this summer to the killers of 16-year-old Ben Kinsella.

Mr Straw, who wants the legislation in place early next year, told MPs that the minimum term will rise from 15 to 25 years. He said: “I propose to introduce a new adult starting point of 25 years for murder using a knife or other weapon carried to the scene with the intention of using the weapon.”

Later he added: “The loss of a loved one in any circumstances is heartbreaking, and even more so when they are the victim of a senseless and appalling murder. It is only right that thugs who carry knives with the intention of using them, potentially to kill, should the opportunity arise, go to prison for a long time.”

Mr Straw intends to introduce the proposals in a statutory instrument — a fast-track parliamentary procedure.

Ben, the brother of Brooke Kinsella, the former EastEnders actress, was murdered in Holloway, North London in June 2008. His killers, Juress Kika, 19, Michael Alleyne, 18, and Jade Braithwaite, 20, were given minimum sentences of 19 years at the Old Bailey. Afterwards the family attacked the jail terms as “simply not enough”.

The announcement came as ministers prepared to outline today a partial retreat over plans to store the DNA samples of thousands of innocent people on the national database. Adults arrested, but cleared, over violent and sexual offences will have their DNA removed from the database after six years instead of 12, as proposed. The Home Office is pressing ahead with plans to keep the DNA of adults arrested and cleared over less serious crimes on the database for six years. The DNA of 17 and 18-year-olds, arrested over violent and sexual crimes, will also remain on the database for six years even if they are not charged or are cleared at a trial.

Shami Chakrabarti, director of Liberty, the human rights organisation, said: “Stockpiling the profiles of millions of innocent people is an unnecessary recipe for error and abuse.”

However, ministers argue that holding the profiles of those without criminal convictions is necessary to track down offenders.

Times Recommends

• Children who front atheist ads are evangelicals
• Killer heels? No, purring kittens
• My Week: Belle de Jour