Mal Fletcher comments

Yet time would show that public interest in a royal wedding can quickly morph into an almost obsessive preoccupation with the minute details of the marriage itself.

Every argument, silently witnessed at the time by household servants, later found its way onto the printed page of newspapers and biographies - sometimes with the connivance of the parties themselves.

So much has changed since then. The press culture has shifted its approach to the private lives of the royals.

Such was the outpouring of grief and fury following Diana's death that news editors quickly backpedalled on the level of intrusion into royal lives. This was not a matter of Victorian forelock-tugging, but of simple human decency.

In time, an entirely new generation of editors and producers emerged who seemed to care far less about royal gossip. In its place they've promoted a more American brand of royal-watching, the soap opera that is modern celebrity culture and so-called reality TV.

Of course, the melodrama that was the married life of Charles and Diana emerged in a world that lacked the intrusive power of today's digital media. There was no Twitter, no Facebook and no video sharing - and almost nobody carried mobile phones.

Today anyone can be a reporter, commentator and producer. Anyone with a mobile phone potentially becomes a paparazza.

So, in spite of a less pushy professional media culture where royals are concerned, the potential for intrusion has grown exponentially. And the worst may be yet to come.

Within the next decade, mobile communications technology will take us into completely uncharted territory, with bio-mechanical personal chips and massively increased computing speeds.

To a degree, of course, a royal marriage is public property, especially given the financial investment by taxpayers in keeping the royal 'firm' afloat. But pushing that line too far means that the natural ebbs and flows, the highs and lows of a marriage cannot be worked through properly, between man and wife.

Anyone who's been married for long knows the importance of being able to talk things through rather than leaving divisive issues to fester unresolved. And the need to keep things as much as possible within the family.

If we're not careful with royal marriages, the entire nation takes on the role of a third set of in-laws.

Some in-laws - like my own, thankfully - are brilliant. But there's another brand of in-law, the type who constantly offer unsought advice and proffer constant criticism, usually without having the benefit of accurate intelligence.

In the end, the hapless couple struggle to find the space to build the lines of communication and the shared memories that make a marriage last.

Imagine how much more difficult this might be if the in-law factor was multiplied millions of times, with everyone in your world knowing - or thinking they know - all about your challenges.

Most of us will gladly enjoy the royal wedding celebrations and then simply wish the couple well. Yet the potential for an unhealthy national preoccupation with the marriage is real - especially given our taste for celebrity gossip.

We all wish Prince William and Kate well. These young people are celebrities but they must not be expected to become part of the modern celebrity culture, with its emphasis on cheap sensation and setting people up for a fall.