A bereaved mother whose 14-year-old son was stabbed to death by a stranger he met via the internet has warned about the “dangers of online predators”.

Lorin LaFave, 47, said she was “heartbroken and lost” without her son, Breck Bednar, who was murdered after travelling 30 miles from home to visit a teenage gamer who he played with over the internet.

Speaking after her son’s killer, Lewis Daynes, 19, pleaded guilty to the crime, LaFave said: “I want Breck’s tragedy to help open the eyes of everyone to recognise the dangers of online predators. It is a very real danger today.”

Breck was found with a fatal stab wound to the neck after leaving his home in Caterham, Surrey, by train to meet Daynes at his flat in Grays, Essex, on 17 February.

Daynes, a computer engineer, initially denied the murder but changed his plea to guilty moments before his trial was scheduled to start at Chelmsford crown court in Essex on Tuesday.

Richard Whittam QC, prosecuting, told the judge Mrs Justice Cox that the murder “involved a sexual or sadistic motivation” and that Daynes faces a whole life term when he is sentenced on 12 January.

Flanked by a court official, Daynes sat expressionless throughout the hearing, speaking only to enter a guilty plea.

The plea change appeared to take everyone in court by surprise, with the jury about to be sworn in and the prosecution preparing to open its case for the three-week trial.

Breck’s parents, oil millionaire Barry Bednar, 49, from Houston, Texas, and LaFave, a US-born teaching assistant, where present for the short hearing on.

In a statement later outside Chelmsford police station, LaFave paid tribute to her churchgoing son who was a member of the air cadets with the 135 Squadron in Redhill.

She said: “I am heartbroken and lost without my Breck and I will never be the same. He was murdered on my birthday this year and so much of me died as well.

“My poor triplets lost not only their adored big brother but also their mother. Breck was my amazing, clever, beautiful boy, a beautiful son who we will miss forever. He had so much potential that he will never now reach. He had so much to give to this world.

“I want Breck’s tragedy to open the eyes of everyone to recognise the dangers of online predators. It is a very real danger today.

“We all need to look after each other. We have set up the Breck Bednar memorial foundation to help raise money and awareness and protect all of our children from danger. I’ll never stop missing my Breck.”

The case will be opened on 12 January 2015 during which Daynes will be sentenced for this crime.”