ON the minus side, it was an appalling wedding speech, and if, all these years later, the guests have any cause to recall it, it was only because the groom seemed to have a quite paralysing attack of stage-fright.

On the plus side, this took place long before the invention of smartphones with video cameras and of social-media websites onto which eternally cringe-making footage could be uploaded. This is only a small blessing.

An awful thing, this fear of public speaking. By and large, I manage not to think of my wedding speech, but every now and again it rises unbidden to the surface. As happened a few days ago, when an invitation arrived out of the blue. Monty Python's Spamalot musical is at the King's in Glasgow from June 1 to 6, a kindly London PR person disclosed in an email. "I just wanted to ask if you would be interested in playing the role of 'Sir not appearing'."

I had three immediate thoughts. 1) Are you sure you didn't mean to send this to a professional actor? 2) If you really did intend to send it to me - why, thank you, but you obviously weren't at my wedding. 3) I imagine the invitation will be extended to lots of other people, so it'd be okay for me to decline.

Sir Not Appearing is a cameo role: you walk on stage, the rest of the cast say 'You're in the wrong show!', you apologise and walk off. Simple as that. "It's a scene that the audience love and creates laughter all round!," the email said, adding that people such as Keith Lemon and Eric Bristow had done it.

One bloke, not a celeb, has blogged about his cameo during Spamalot's West End run: "The audience's reaction was great, and I was grinning from ear to ear," he wrote. "It was just brilliant."

I try to think what would happen if I took up the offer: I would, in rapid succession, be too frightened to walk out in front of the audience and would have to be pushed on by an impatient member of the backstage crew: I'd throw a beseeching glance at the cast as if to say, 'What's my line?!'; a puddle would appear at my feet. And all of it soundtracked by pure, stone-cold silence.

"Public speaking is said to be the biggest fear reported by many American adults, topping flying, financial ruin, sickness, and even death," said one US website I consulted yesterday. Too true. So, apologies, Spamalot PR. It was a generous invitation, really, but you'd be better off with someone else.