Police investigations into allegations of child sex abuse by former Rochdale Liberal Party MP Sir Cyril Smith must be pursued "to the bitter end", Deputy Prime Minister Nick Clegg has said.
Greater Manchester Police acknowledged last year that young boys were victims of "physical and sexual abuse committed by Smith" at a children's home he opened in the 1960s.
On three occasions files were passed to the Crown Prosecution Service but no action was taken.
A report by Channel 4's Dispatches last week revealed details from the original police file containing allegations against Smith, and raised concerns that senior figures within the establishment leaned on prosecutors to ensure he was not brought to justice.
Lawyers acting for the victims have said they are considering action against the Liberal Democrats.
Smith served as a Liberal councillor in Rochdale from 1950 and became mayor in 1966. He was elected a Liberal MP in 1972 and became a Liberal Democrat on the formation of the new party before leaving Parliament in 1992. He was knighted in 1988.
At the time of his death in 2010, Mr Clegg said he was "deeply saddened" and described Smith as "a larger-than-life character and one of the most recognisable and likeable politicians of his day".
On Monday, the Lib Dem leader told BBC Radio 5 Live: "I'm shocked and appalled by the allegations I've seen."
Some of these allegations were about things that apparently may have happened before I was even born and all of them before the Liberal Democrats were even formed.
"This does go back some way in time but of course if you are a victim, it doesn't matter how many years have intervened between the abuse and the time it comes to light.
"It needs to be investigated and victims need to feel that justice is on their side.
"I would like to see the police and the long arm of justice even after all these long years finally pursue this to the bitter end."