What good is an investigation into the Princess Diana BBC interview from 25 years ago?

The whole affair is nothing but a PR exercise designed to rebuild the broken relationship between the BBC and the monarchy, writes Janet Street-Porter

Panorama drama: Diana and Martin Bashir in 1995 (AFP/Getty)

I’m not sure what a inquiry into the circumstances surrounding a BBC interview that took place 25 years ago between two consenting adults can achieve.

Is the point of the exercise to reinforce the notion that Princess Diana was unstable, incapable of making a rational decision? Or is it to brand the reporter someone who used questionable methods to achieve his aims, methods which miraculously have gone unchallenged for decades?

If Martin Bashir has committed a crime, then it is a matter for the police. If Princess Diana was deceived and – as a result of being fed any untruths – participated in something she would not have otherwise considered, that is a very tricky case to prove. Either way, one of the pair will have their reputations dissected and found wanting.