Your leader on expert evidence only touches the surface of the problems surrounding the presentation of expert evidence in Scottish courts ("Bringing expert minds to bear on the law", April 20).

Although defective testimony represents a small minority of the total, tragically it can lead to the innocent being deemed guilty and the guilty remaining undetected and unpunished. The financial costs are enormous. The costs in human terms are incalculable.

Inefficient scenes of crime procedures, defective analysis by forensic scientists and a failure by prosecution and defence lawyers to ensure the quality of their experts and the relevance of their testimony all contribute to a growing problem. Laissez-faire judges who will not or cannot act as gatekeepers to expert evidence and provide guidance to uncomprehending juries only serve to compound matters.

Lessons are not being learned. Dubious fingerprint evidence nearly condemned my daughter, Shirley McKie, to prison and yet many of the recommendations of the resultant £5 million public inquiry gather dust on the shelves of those responsible for implementing them.

As the Kimberley Hainey case dramatically shows, the appeal judge's "quack" comments can divert attention from these continuing system failures and unfairly put at risk the reputations of the many skilled and dedicated experts whose testimony can play a vital part in ascertaining guilt or innocence. How much longer will these experts accept this lottery with their livelihoods?

The old checks, balances, systems and procedures for evaluating forensic evidence are no longer effective. We require to develop a consensus among those who manage our justice system that change is necessary and must be realistically funded. The Law Society, Faculty for Advocates, Crown Office, Judicial Institute and politicians all need to sit up, take notice and implement training programmes and procedure reviews aimed at ensuring that in Scotland expert evidence can be relied upon to deliver justice for all concerned.

Iain A J McKie,

27 Donnini Court,

South Beach Road,