A FAMILY is grieving the loss of “the best granddad anyone could wish for” after he was stabbed multiple times in a frenzied road rage killing.

Donald Lock, 79, from Worthing, was repeatedly stabbed and left for dead by an enraged motorist on the A24 in Findon just before 8.40pm on Thursday.

His death came as new statistics released yesterday show knife crime in Sussex has increased dramatically in recent years - jumping from 481 crimes involving knives in the year ending March 2013 to 873 crimes in the year ending March 2015.

Mr Lock, who police say was travelling alone, is thought to have shunted the back of his attacker’s ‘pale and old-style’ car before getting out of his vehicle. He was confronted and stabbed multiple times. His killer then got back in his own car and drove away south on the A24.

The air ambulance crew and paramedics desperately carried out first aid on Mr Lock, who was a keen cyclist and member of Worthing Excelsior Cycling Club, but he was pronounced dead at the roadside near the Wyevale Garden Centre.

In a tribute posted on Facebook, the victim's grandson Ashley Goodlad said: "This sick person has taken away the best granddad anyone could wish for. I still can't believe this is real. It has torn my family apart with pain."

Mr Lock’s family and friends yesterday visited the crime scene to lay floral tributes.

John Lucas, who had known Mr Lock for more than 50 years, said: "It's such a terrible thing. He was an unbelievable guy. He would do anything for anyone.

"I can't understand how it happened. He wouldn't have got out of the car and caused any trouble at all.

"He wasn't that type of guy. He has been in the cycling club - Worthing Excelsior Cycling Club - more than 60 years."

Mr Lock lived with his wife Maureen in Welland Road, Worthing.

A neighbour said: “We heard what happened and just can’t believe the news. It’s so sad.

"We’d always see him coming in and out of the road on his bike.

“I can’t imagine what his wife is going through. It’s such a real shame.”

At about 2pm yesterday detectives announced they had arrested a 34-year-old Worthing man in Hillbarn Lane, Worthing, on suspicion of Mr Lock’s murder.

Detective Superintendent Adam Hibbert, of the Surrey and Sussex Major Crime Team, said: "Mr Lock was the victim of a frenzied attack that he had no chance to defend himself against.

“A man is in custody on suspicion of murder. I continue to appeal to anyone who witnessed the collision on the A24 at 8.40pm last night or who may have CCTV or dashboard cameras of the area at that time, to come to assist our investigation. They should contact police on 101 or email 101@sussex.pnn.police.uk quoting Operation Wise."

Forensics teams combed both carriageways of the A24 yesterday as they searched for evidence.

The road is likely to remain closed today from the Black Horse pub up to the Wyevale Garden Centre.