A sexual predator told one of his victims he could stop - but only if he found another boy to take his place.

The true scale of Arthur Warwick's depravity emerged as the 58-year-old was yesterday sentenced to life in prison. He must serve a minimum of 13 years before he will be considered for release.

Carlisle Crown Court heard how Warwick had previously admitted to 29 child sex offences.

These included five rapes on children as young as nine; the attempted rape of a nine-year-old; a series of serious sexual assaults; and a number of indecent images charges.

His victims, three boys and a girl, were systematically abused over a period of more than 40 years.

The court heard how Warwick's sick life of depravity was only discovered when he was caught in a Cumbria Police sting operation.

He travelled to Whitehaven, believing he was meeting a 13-year-old boy he had befriended online, but in fact was met by an undercover police officer.

Warwick was arrested, and when his home was searched, 20 indecent images of children were found on his computer equipment. A third of these were classed in category A - the most serious.

The paedophile admitted a charge of attempting to meet a child following sexual grooming, and coverage of that court case led to an abuse victim coming forward.

Three other complainants later took the brave step of speaking out.

Prosecutor Jacob Dyer gave yesterday's hushed court details of Warwick's terrible crimes, as he showed little emotion in the dock.

Of the victims, Mr Dyer said: "He groomed them, offering cigarettes and sweets as inducements to carry out sexual activities.

"In each case the offending was repeated, sometimes over a period of years.

"At times, in relation to some of the victims, there were threats made to ensure the abuse was not disclosed."

In the case of one male victim, Mr Dyer added: "The defendant told him that he could stop if he found another boy to take his place."

Moving statements provided by the four victims detailed the profound impact caused by Warwick. One described him as a "dirty monster".

Marion Weir, defending Warwick, admitted: "He concedes, as I concede on his behalf, that there is no mitigation.

"There is nothing he can do to alleviate the distress. Remorse, in many ways, seems to be an empty sentiment."

Passing sentence, Judge Davies told Warwick, previously of Roundthorn, Penrith, he was a "sexual predator".

"The harm you have caused is incalculable," said the judge. "You are a paedophile.

"You are a dangerous sexual predator who has caused mayhem, devastation and personal despair to several victims and their families."

Noting Warwick was a man of previous good character, Judge Davies said the offences had been committed "under a guise of respectability".

"You exploited everyone and they have all been damaged. All these people are innocent. They are not responsible. That responsibility lies with you, and you alone," said the judge.

Warwick must serve a minimum of 13 years before he will be considered for release by the parole board.

But Judge Davies stressed: "Mr Warwick, you may never be released."