The mother of a murdered water engineer today called for life sentences for killers to mean life.

Judy Tilbury was commenting after schoolboy Alan Pennell was jailed for life for stabbing to death fellow pupil Luke Walmsley.

She said killers given life were often freed early and were able to start new lives.

Mrs Tilbury, 64, has spoken out on TV and radio and vowed to continue the fight "until the day I die".

Her son Mathew, 24, died when his skull was crushed with a single blow from a baseball bat when he tried to stop a fight in Sheepcote Valley, Brighton, in 1996.

The following year, father-of-two Jamie Cooper, then 20, from Woodingdean, Brighton, was jailed for life for his murder.

Mrs Tilbury said Cooper could be freed in five years after serving the minimum "life" term of 12 years.

She said: "He'll be about 31 and young enough to start a new life.

"Yet he intended to kill my son. It was one massive blow to Mathew's head, not his arm or leg. He hit Mathew to kill him.

"I've always wanted to get hold of Cooper and ask him why he hit Mathew so hard.

"When the intent to kill is there, then there is no doubt in my mind murderers should stay in prison. They should not be allowed another life."

Mrs Tilbury said she felt deeply for Luke's family.

Pennell, 16, stabbed Luke, 14, through the heart in front of pupils at their school in Lincolnshire.

Luke's mother Jayne said of Pennell: "He was an evil boy who was a bully. That boy still has some form of life in front of him. Luke has not."

Mrs Walmsley said she believed anyone who took another life should be prepared to give their own.

She said: "I believed before this happened in an eye for an eye. Luke has been taken from us and we will never be the same again."

Mrs Tilbury, from Hassocks, said life without her son was equally painful.

She often cried when she thought of him.

She said: "Mathew would tease me by tipping pictures on the wall, making them crooked. It's strange but it happens now all by itself sometimes, like he's still here, pulling my leg.

"I think about him every day, especially when there are no clouds in the sky because he used to love the summer so much.

"I call them Mathew days."

Mrs Tilbury keeps photographs of her son round her home, along with tribute poems written by relatives and friends.

She has no time for "do-gooders" who want her to forgive.

She said: "Life should mean life and I won't stop saying it until the day I die."