A former scout leader who sexually abused young boys during trips and visits to his home was jailed for five years and four months.
Michael Medhurst subjected the cubs and scouts, aged between eight and 13, to a catalogue of indecency, often in tents in Leicestershire, when they went on trips to Mallory Park and Castle Donington race tracks.
Katya Saudek, prosecuting, said: "He made full admissions in interview, saying he was using his role as a cub and scout leader so he could abuse them.
"He befriended those who had a common interest, such as motorbikes.
"He befriended parents to allow himself more access to the children.
"He abused boys on a frequent and multiple basis, at their homes, at his home or when away on trips.
"It's strongly suspected there are many more victims."
Medhurst, 62, of Coney Green Drive, Birmingham, admitted 10 offences of indecent assault on boys under 16 and one count of gross indecency on a boy under 14, between September 1981 and September 1987.
The court heard that in 1991 he was jailed for six years for 18 offences of gross indecency and indecent assaults upon other scouts and cubs during the same period.
In 2011 he was prosecuted for downloading more than 3,000 indecent images of children.
One of the four victims, in the latest case, campaigned to get the case re-opened against Medhurst and went into the witness box to read his victim impact statement.
Looking at the defendant, who stared straight ahead with his arms folded, he branded him a "calculating predatory paedophile with no concern for his victims" and urged others who may have suffered at his hands to come forward.
The victim was among three who attended court; but all four claimed to have been robbed of their childhood innocence and "haunted" by his abuse, which had completely ruined their lives. Some were suicidal at times and all suffered from depression and had nightmares about being molested in their sleeping bags at night.
One said: "I now realise he was grooming my parents."
The cub and scout groups were in the Birmingham area; where the victims herald from.
Medhurst told the police last year: "It's all a bit of a blur; it's difficult to differentiate between boys.
"I don't know how many because I abused so many."
Miss Saudek said he would gain the parents' trust so he could abuse their children, often many miles away from home, including in bed and breakfast accommodation.
Children were allowed to visit his home after cubs and play on his computer, have trips on his motorbike, and he would give some of them alcohol, money and gifts.
Others would avoid him and he was generally nicknamed "Bummer Mick " amongst cubs and scouts, said Miss Saudek.
Medhurst, who represented himself saying he had been refused Legal Aid and could not afford a barrister, said from the dock: "At the time I didn't understand the seriousness of the offences or the harm caused to the victims.
"I do understand since my release from prison - and I've done my best to avoid circumstances where I could be tempted to offend again.
"I wish I could turn the clock back and undo what I did, but I can't.
Turning to his victims, he said: "I'm deeply sorry, I wish there was something I could do to put it right."
Judge Robert Brown said: "We've heard of the lasting impact and real and deep hurt you've caused to these four men.
"You abused the trust that they and their parents put in you by sexually abusing them at every opportunity you could find when they were with you.
"You took them to sporting events, camping trips and engineered opportunities where you could take advantage of them.
"You've admitted, in the pre-sentence report, your behaviour was manipulative and systematic.
"These victims weren't included in the original investigation.
"They've been shackled by the memory of the abuse which still haunts them.
"I'm not sure if you understand the extent of the harm you've caused, but it lives with them every day."
Afterwards, investigating officer, DC Jamie Carr, said: "Medhurst abused his victims over many years, befriending them and building up trusting relationships with them and their families - using his position of trust as a scout leader to do so.
"This has been an emotional time for the victims in this case, who have been dealing with the abuse secretly and the conclusion hopefully offers some comfort. "The victims in the case have shown incredible bravery in coming forward to talk to us and report what Medhurst subjected them to."
If you have been a victim of indecent assault, contact police on 101, asking to speak with the Child Abuse Investigation Unit.