Witnesses said Joseph was smirking as he left the bus

He met his girlfriend in The Agricultural pub in north London for a couple of drinks after work.

Earlier that day, hundreds of miles away Anthony Joseph had been released from Forest Bank prison in Manchester.

The 22-year-old took the train to London, arriving at Euston Station. He then made several phone calls to the man he blamed for putting him in jail, threatening to kill him and his family.

When Mr Whelan and his girlfriend Kerry Barker, then aged 38, ran to catch the number 43 bus, they crossed paths with Joseph, who boarded the bus carrying a bag of chips.

Joseph, who was sitting at the back of the bus on the top deck, began throwing chips at an American woman as she spoke to her husband on her mobile.

Ms Barker reported that Joseph then began throwing chips at her and one hit the back of her head.

Several passengers chose to move downstairs rather than seek a confrontation.

Costly decision

But Mr Whelan was not prepared to sit down and do nothing. He got up and approached Joseph.

Ms Barker witnessed her boyfriend's murder

CCTV footage on board captured the struggle that ensued when Mr Whelan asked Joseph to stop throwing chips.

Joseph, who habitually carried a knife, became verbally and physically aggressive.

In an attack lasting no more than 30 seconds, Joseph stabbed Mr Whelan seven times, in his thigh, back and heart.

Mr Whelan followed his attacker downstairs but collapsed and never regained consciousness.

Witnesses said Joseph appeared to be smirking as he left the bus in Holloway Road, north London.

But his defence team argued that was a sign of his then undiagnosed schizophrenia.

Terrible memory

Investigating officer Det Insp Dave Corby said he was pleased Joseph had admitted his guilt.

Mr Whelan had asked Joseph to stop throwing chips at passengers

He said: "The most important thing here is to remember that Richard lost his life as a result of this appalling attack.

"His family lost a beloved son, brother.

"His girlfriend lost a boyfriend. Not only that, she witnessed him being stabbed to death and dying in front of her."

Ms Barker described Mr Whelan as a private, quiet man who got on well with people.