It's perhaps time that people were more experienced in criminal matters where the law is becoming more complicated

John Scott

He makes the claims in a BBC Scotland documentary about the Chhokar affair, to be broadcast on Tuesday evening.

Mr Scott said: "There is no audit of success rates and you don't have a league table for individual prosecutors.

"I think it's time that we looked again at who is prosecuting our most serious cases and it's perhaps time that people were more experienced in criminal matters where the law is becoming more complicated."

Frontline Scotland has investigated issues surrounding the Chhokar case which saw three men tried and acquitted of murdering the Indian waiter from Lanarkshire.

The programme also hears from Professor Chris Gane of Aberdeen University, an expert in criminal law and legal proceedings, who argues that there is a lack of prosecutor accountability in Scotland.

The Chhokar family have called for a public inquiry

"If the public prosecutor makes a mistake there's no guarantee that we would get to know about it, and there's no guarantee that that decision could be publicly held to account."

Mr Chhokar, 32, from Lanarkshire, was stabbed to death during an attack in 1998 outside his girlfriend's house in Overtown.

Ronnie Coulter, 32, of Wishaw, was initially brought to trial.

He was cleared of murder but convicted of a lesser charge of assault after a six-day trial.

The two other men, Andrew Coulter, 19, and David Montgomery, 23, were later tried and also cleared of the fatal attack. Coulter was jailed for 12 months for assault.

Murder victims

The programme features footage from a PETAL (People Experiencing Trauma and Loss) meeting in Hamilton where parents of other murder victims say they feel let down by Scotland's legal system.

Chairman Joe Duffy said: "I would welcome any inquiry that the Chhokar case can actually generate within the Scottish legal system to ensure changes are made."

The Crown Office declined to participate in the documentary while inquiries into the Chhokar case were under way.

A report by a senior Northern Ireland judge into the case is due out next month and an inquiry is also being held into the way the Crown Office liaised with the family.

The parliament's justice committee has launched a full scale inquiry into all aspects of the Crown Office and the Procurator Fiscal Service to find out if they are failing the very people who need support the most.

MSPs will also look at staffing levels, fiscal fines and plea bargaining - as well as relations between the Crown Office, the Scottish Executive and the police.

Frontline Scotland is to be broadcast on BBC One Scotland at 2235BST.