Gary Gavin, 24, was told by Judge Rhys Davies QC at Manchester Crown Court that he was a danger to the public. 'It may well be that you will never walk the streets of this city again.'
Gavin, of Tunstall Court, Blackley, Greater Manchester, had pleaded guilty at an earlier hearing to 12 indecent assaults, three charges of buggery and two of attempted buggery.
The court heard that 11 of his victims were under 15 and included an eight-year-old girl.
Gavin, sometimes using a mountain bike, preyed on his victims in parks and open spaces. In addition to the life sentences for buggery, he was given consecutive sentences totalling 30 years for the other offences.
The judge told him: 'You have pleaded guilty to a line of offences which represent an unparalleled series of attacks against women, young girls and young boys.
'In many cases your assaults were committed upon young girls on the threshold of sexual awareness. These are the types of offences which give rise to dread in the heart of every parent of every child.'
Before some of the offences, Gavin had pretended to be a police officer so he could take young children away. Gavin had given himself up to police following a confrontation with a brother who realised after a BBC Crimewatch programme that he was a sex attacker.
Gavin's victims and their families packed the public gallery for the sentencing. Children under 14 were given special permission to attend because their parents thought it would help them come to terms with their ordeals.
Johnathan Geake, for the prosecution, said three of the offences were against women, nine against girls and three against boys and were carried out between February 1992 and March this year. He said Gavin had spent a young life in care and institutions and claimed always to have had difficulty with personal relationships.
'He also claimed to have suffered a loss of self-confidence when appearing in a small part in an amateur dramatic production at Christmas 1991,' Mr Geake said.
'After this he brooded on his own for a couple of months and then embarked on a particularly horrifying series of violent sexual assaults upon women and children.'Reuse content