Sir Cyril Smith did visit a guest house linked to a child sex investigation, the Metropolitan Police has said.
Scotland Yard's Operation Fernbridge is investigating allegations of abuse at the former Elm Guest House in Barnes, west London.
"We can confirm Cyril Smith visited the premises," a Met spokesman said.
The Crown Prosecution Service has admitted the former MP should have been prosecuted for 1960s abuse in Rochdale. Sir Cyril died in 2010 aged 82.
It was alleged he raped boys at Knowl View and abused boys at Cambridge House Children's Home, a privately-run care home in Rochdale which closed in 1965.
He had a long association with Knowl View, where he was on the management board when he was a councillor.
Sir Cyril was originally a Labour councillor in Rochdale and later a Liberal then Liberal Democrat MP for the town from 1972 to 1992.