Fortunately, at the kind of school where I was sent it was damn well assumed you knew about that kind of thing before you arrived. If a pupil wasn’t au fait with human reproduction then, Good Lord, go and look at the lavatory walls.

I also managed to avoid any instruction from my parents. But last week my 10-year-old daughter brought home a note from her school which explained that sex education was coming up shortly and any parent who wished to preview the school’s video collection before giving consent was welcome to attend Monday morning, straight after assembly. “Please Dad, will you go,” Miranda asked me. “I need to know if there’s any snogging.”

Knowing my daughter’s proclaimed aversion to couples kissing on TV, yesterday morning I took my place among the mums in the music room and awaited illumination. The school had assigned its most sensible and down-to-earth teacher to the task of educating us parents. Mrs B explained that their videos put puberty and reproduction in the context of how our bodies develop. For this reason the first video was devoted to how babies turn into children. Only halfway through would we see diagrams of how various bits got bigger, developed hair and the potential for creating yet more babies.

We had been effectively forewarned, but what I wasn’t prepared for was the vintage of the video in question. The couple who were bathing their twin boy and girl wore flares and the man actually had a Noel Edmonds beard. The actress narrating spoke with a precision rarely heard these days. When she told us “Baby Martin has a penis. All boys have a penis.” I half-expected her to add “Andy Pandy has a penis too.”

Video Two got onto the yukky stuff with what must - in the 1970s - have been breathtaking footage of the six-week-old foetus in utero. Personally, at the age of 10 I might have had to leave the room at this point because of all the slime and pulsing blood vessels, but anyone who has sat through Alien ought to be able to cope. Worse was to come with a shot of the man with the Noel Edmonds beard, who had just bought his wife a pram along similar dimensions to the carriage that transports our Queen to the state opening of Parliament.

Then the narrator asked the big one: “But how are the babies born?” To my total surprise we then cut to shots of a cat producing its kittens, dangerous stuff if your daughter still resents the fact that you had Snowy neutered three years ago. The birth of humans was safely left to a diagram which, in my opinion, is how it should always be done.

Finally we came to Video Three which - Miranda’s teacher explained - treats conception from the point of view of us all deriving characteristics from two parents. After a lot of footage about whose eyes and whose nose we might inherit - and a diagram of a young boy growing up, developing pubic hair and coming to look in adulthood remarkably like Gordon Brown - we arrived at the fact that the ova are to be found in the adult female and the sperm in the male. The narrator then confirmed what I had always suspected (namely that the man’s penis put the sperm inside the woman’s vagina) but we weren’t shown quite how Gordon Brown did this. “The man and woman become very close,” said the narrator and indeed we did see a drawing of a naked lady placing her head on Gordon’s shoulder, but what was going on just below shot was left to our imaginations.

Personally that suited me fine and I was happy to leave the preview session and give my consent. As Miranda’s teacher pointed out, the exact details of what goes where can be discussed in class or left for the parents to fill in. Failing that, if Miranda ever meets the Chancellor of the Exchequer I suppose she can ask him.

I am glad I went simply because if she asks any questions I’ll know exactly what they relate to. That will cut down the time spent in dumbfounded embarrassment to a minimum. I am also very reassured that Miranda’s teacher is the kind of woman who can deal effectively and sensibly with any questions that might be raised. But most of all I now can reassure my daughter that there was no snogging whatsover. Not even in the back row of the music room.

Adrian Mourby is a novelist and freelance writer.