Twenty men have come forward to claim they were abused by late MP Cyril Smith, according to a police investigation.
Greater Manchester Police said one of the alleged victims accused the former Rochdale Lib Dem MP of rape.
Officers are investigating the scale of alleged abuse at the hands of Smith, who died in 2010 without ever facing prosecution.
Police said, of the 20 alleged victims who have now come forward, 10 are thought to have been abused by Smith at Cambridge House, a school for difficult children in Rochdale, and five more at Knowl View School, also in Rochdale.
A further five are alleged to have been abused by the MP at various location across the Greater Manchester area.
All those offences are alleged to have taken place between 1960 and 1987.
Police are also investigating whether the alleged crimes committed by Smith may have been covered-up by people at the "very top of the establishment".
The investigation into Smith is part of a wider inquiry into allegations of sexual and physical abuse which occurred at Knowl View school for boys.
Since the start of the investigation, 24 people have come forward with allegations they were abused at the home between 1969 and 1995. Officers have so far interviewed under caution 21 men aged between 35 and 80 for a variety of offences, including sexual and physical attacks.
Det chief supt Russ Jackson, from GMP's Serious Crime Division, said: "The investigation into abuse at Knowl View School continues and since the start of the inquiry 24 victims have come forward.
"These are serious complaints made against both staff and pupils at the school and we have a team of experienced detectives working on the case.
"The passage of time makes these investigations difficult and complex, but we are committed to supporting victims who now have the strength to come forward as best as we can.
"I would encourage anyone who was a victim of either sexual or physical abuse to come forward and speak to police, as the more evidence we have the better the chances are of bringing abusers to justice.
"We completely understand that for many people they will not want to relive the abuse they suffered, but for those who do want to come forward I want to give you complete confidence that your complaints will be treated seriously and thoroughly investigated."
Allegations surrounding Smith first emerged in 1979. Despite being investigated by police after more than 144 complaints, Smith was never charged for any offence.