POLICE Scotland are investigating a Labour peer over allegations he sexually abused a teenage boy in the 1970s, according to reports.

The development comes after a controversial decision by the Crown Prosecution Service (CPS) not to charge Lord Janner, following claims he abused young boys at a care home in Leicestershire.

It is claimed the allegation was made at an Edinburgh police station in 1991 that Lord Janner, then an MP, had taken a boy with him to Scotland in the 1970s, where he subjected him to serious sexual assaults.

Police Scotland have reportedly located "relevant files" which show a complaint was made by the alleged victim to a police station in the capital in 1991.

The force is said to have spent several weeks trawling through archived files before finding documents relating to the case, which has led to the new investigation.

A police source told the Daily Mail: "We have located the relevant files which show a complaint was made."

Lord Janner is thought to be among 37 people in the public eye who are among 110 suspects identified by Scottish police probing historic sex abuse allegations. There are 58 separate inquiries under way.

The CPS made the decision not to charge the 86-year-old in April, saying he would not be fit to stand trial because of his dementia.

It was criticised at the time by a senior officer from Leicestershire Police, who said it would do little to encourage sex abuse victims to come forward.

A Crown Office spokesman was: "We have not received a report in relation to this matter."