A former swimming teacher who admitted abusing children in offences dating back to World War II has been jailed for 12 years at Leicester Crown Court.
Roy Clarke admitted sexually abusing boys and girls
Former swimming coach Roy Clarke, 79, from Duncan Road in Aylestone, admitted sexually abusing boys and girls between 1942 and 2003 at a previous hearing.
Leicestershire Police described him as "vindictive, predatory and dangerous".
The prosecution came about after a woman came forward last summer to report an historical case of abuse.
Clarke, who used to work with youngsters as the Leicester Amateur Swimming Association county coach, admitted 16 offences including gross indecency and assault, which took place at his home.
He was arrested there last September.
Police managed to trace 30 people who all said they had been abused by Clarke at his house. Most thought they were the only ones being abused.
In February, Clarke admitted 16 counts of indecency with five girls and three boys aged under 16.
Jailing him, Judge Christopher Plunkett said: "For a period of more than 50 years you preyed on young, vulnerable children - five, six, seven and eight years old and sometimes a little older.
"In a premeditated way you won their trust and the community's trust, but you did so in a way in which you could indulge in your vile desires."
After the case, Det Insp Lee Hill, who led the inquiry, said: "It's quite right that he's brought to justice. His health has only deteriorated over the last few months since his arrest.
"And certainly during his period on remand he received pornographic material through the post by mail order - (he is) still a person very interested in sex.
Det Con Debbie Timms, of Leicestershire Police, said: "Even during the most horrific (offences) that he did admit, there was still an element of blaming the child.
"I wouldn't say that throughout, he's ever showed any remorse and to this day it's always been the child that's in the wrong and never him."
'Not too late'
Mr Hill said he feared many more of Clarke's victims had never come forward.
Most of the children groomed and abused knew Clarke as they were local youngsters from the Aylestone area of Leicester where he lived.
"It is not too late for people to come forward and tell us about it," he said.
"We are committed to both victim and witness welfare and we have specially trained staff who can offer full and confidential support."
One of Clarke's victims, Malcolm, who was abused over a four-year period in the 1970s, said: "He is evil, and as far as I'm concerned, the only place he deserves to go is hell."