Scottish legal authorities have said they will not pursue an allegation that the late Greville Janner sexually abused a boy during a trip there in the 1970s.
The alleged victim, who was living in a Leicestershire children's home at the time, has told police Janner sexually assaulted him during a business trip.
The allegation was reportedly passed to the police in 1991 but did not result in a charge.
Police Scotland confirmed last year it had launched a new investigation into the allegation.
The Crown Office and Procurator Fiscal Service (COPFS) has confirmed there will be no legal action.
Lord Janner was accused of 22 sexual offences against boys between 1963 and 1988 but died, aged 87, shortly before Christmas.
His death ended the prospect of his alleged victims' evidence ever being tested in a criminal court in England and, now, Scotland.
His family has insisted he was innocent of any wrongdoing.
Instead, the allegations will be examined in detail at the Independent Inquiry into Child Sexual Abuse.
The inquiry, chaired by New Zealander Justice Lowell Goddard, will examine why Lord Janner was not charged with offences against children when he was alive and well.
Liz Dux, specialist abuse lawyer from Slater and Gordon, who represents the victim, said: "This decision was entirely expected and does nothing to undermine the validity of my client's allegations.
"Scotland has a different criminal justice system.
"Furthermore, there could be no prosecution in any criminal court following Janner's death.
"His death has denied my client – and all alleged Janner victims – the last chance of having these allegations heard and tested in a criminal court.
"My client now looks forward to giving his evidence to the Goddard Inquiry so that independent findings of fact can be made and this unhelpful speculation can finally be resolved as to what happened so many years ago."
In a statement, the COPFS said: "The Procurator Fiscal received information from Police Scotland relating to an allegation against Lord Janner concerning sexual assault.
"There is insufficient evidence in this case due to a lack of corroboration.
"Furthermore, the law does not allow us to indict an accused who is deceased. Therefore there will be no criminal proceedings."
Organisations such as the Crown Prosecution Service, Leicestershire Police, Leicestershire County Council and the Labour Party are to be questioned by the Goddard inquiry about their knowledge and handling of historical allegations against the former Labour MP for Leicester West.