Scores of youngsters left their Roman Catholic church in tears yesterday after paying their respects to the family of Jimmy Mizen, the 16-year-old boy who was stabbed to death at a bakery in southeast London.

Jimmy’s parents, Margaret and Barry Mizen, and his six brothers and two sisters were joined by 300 people for Mass at Our Lady of Lourdes church in Lee, just 200 yards from the site of the attack. Jimmy’s eight-year-old brother, George, was one of the altar boys.

Father Edward Perera said that the service, which included a two-minute silence for Jimmy, had been deeply moving. “I have never seen a parish so numbed and shocked,” he said.

Jimmy was killed during an unprovoked argument with another youth at the Three Cooks bakery on Saturday morning. He died in the arms of his brother Tommy.

Police said that the youth had been “intent on violence”. He went into the bakery and asked Jimmy to go outside for a fight but Jimmy refused. The aggressor then smashed in the glass door of the bakery, picked up an advertising board and started waving it around. Jimmy’s throat was cut with a shard of glass. Paramedics were called but he was pronounced dead at the scene. He is the 13th youngster to be killed in London this year.

Police said last night that a “significant witness” – a white, middle-aged man who was inside the bakery at the time – had come forward to help.

Jimmy, a former altar boy, normally worked at his father’s shoe-repair and key-cutting shop on Saturdays, but had been given the day off because Friday was his 16th birthday. He had gone down to the shops to buy his first lottery ticket. Outside the church yesterday, Mr Mizen, vice-chairman of governors at St Thomas More Catholic Comprehensive school in Eltham, described his son as a “gorgeous and loving boy” with a sense of decency.

“He was very proud of his family,” he said. “He had six brothers and idolised each one of them. I want to get the right image of Jimmy across to you. We are a close family and we tried to bring him up with good values. he was an uncomplicated young fella who was not afraid of hugs. There was no bad stuff about Jimmy. He was a fine, fine young fella. He was very happy, we’re a very close family and we brought him up with good, decent values, and Jimmy had them.”

He said that his son had been doing work experience for Southwark Council in their housing department and had done so well that they had created an apprenticeship for him. He had been due to finish school today.

Mrs Mizen said that her thoughts were with the parents of her son’s killer. “He was attacked by a boy we probably know,” she said. “I feel sorry for the parents. We have lovely memories of Jimmy. They will have such sorrow for their son. They have got real, real sorrow.”

Jimmy’s brother Danny, 30, said: “Jimmy was the life and soul of the family. If you asked any of the brothers and sisters, I’m sure they would say Jimmy was their favourite. He was just a good guy, really enthusiastic in everything he did and always had time for all of us.”

Jimmy’s grandmother said that her grandson rang her the night before he died to thank her for his birthday money. “He really was a smashing boy,” she said. “All the family are lovely and there has not been one bit of trouble from any of the brothers.”

Alison Martin, whose son George was a close friend, said: “Jimmy was one of the most popular boys in Year 11. He always had a smile on his face and was such a nice boy. He was not the type of lad who would go looking for any trouble, he was very well behaved and well liked.”

Detective Chief Inspector Cliff Lyons said: “Jimmy was a person of immaculate character, as is everyone from the Mizen family, and he is a victim of an entirely unprovoked and vicious attack and my heart and condolences go out to the family.”

He said that the killing was not gang-related. “This was an assault with an excessive use of violence; an unprovoked attack on a decent young man,” he said. “For the sake of the family and this investigation, I would like people to come forward.”

Police were hoping for an early arrest but searches of several addresses failed to locate the suspect. Yesterday officers carried out a fingertip search of the area outside the bakery.

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