The Yorkshire Ripper was helped to kill by a stranger he never met and who lived 100 miles away.

In one of criminal history’s cruellest hoaxes, John Humble tricked police into believing the serial killer was Wearside Jack, a man with a gruff Sunderland accent.

That was despite women who survived Peter Sutcliffe’s attacks saying he sounded like a local.

Humble, for reasons he never fully explained, delighted in taunting the press and detectives with letters and an infamous tape, anonymously claiming he was the killer who was terrifying northern England in the late 1970s.

File photo dated 20/2/1981 of Bradford lorry driver Peter Sutcliffe, under a blanket, arriving at Dewsbury Magistrates Court charged with the murder of 13 women and attempted murder of seven others. Sutcliffe, known as The Yorkshire Ripper serial killer, has died at University Hospital of North Durham after being transferred there from maximum security HMP Frankland, where he was an inmate. PA

He sent it to assistant chief constable George Oldfield in 1979, saying: “I’m Jack.

“I have the greatest respect for you, George, but Lord, you’re no nearer catching me now than four years ago when I started.”

The ruse hijacked the already-cumbersome police inquiry and diverted resources from the streets of Yorkshire and the North West to Wearside.

The vast sum of £1 million was spent on adverts to try to help find Wearside Jack.

Dialect experts analysed the recordings and identified the exact area of Sunderland the suspect could be from, leading to 40,000 men in the North East being investigated.

The tape and letters convinced officers because they included details which police, wrongly, believed had never been made public.

Though Sutcliffe had been questioned by police, his handwriting did not match that in the hoaxer’s letters.

Wearside Jack: Hoaxer who helped Yorkshire Ripper from 100 miles away