These days there aren’t the obvious differences between state and private that used to obtain when Billy Bunter and the Bash Street Kids belonged not just to different comics but different worlds. Then the accents were different, the syllabus was different and the clothes that pupils wore told you straight away whether or not their parents paid over the odds.

Nowadays, when it’s fashionable for everyone to affect threads and vowels that might have come off the back of a Sarf London lorry, it’s more difficult to tell the two sectors apart. Both follow the national curriculum, produce booklets describing the school’s ethos and have headteachers that like you to call them Mike. The one big give-away is hair colour. Lookng for a suitably boy-free zone, Ginny’s mother and I have been forcibly struck by blondes. In a classroom full of 30 girls if 20 of them are as ashen as Sigourney’s wig you can guarantee this is a fee-paying school, particularly if the other 10 are Asian.

What is it about blonde hair that betokens parents with enough spare cash to educate their daughters privately? Casting a glance across Ginny’s old class at St Judes the only blonde head I can remember was Torville who’d had an accident with his sister’s bleach bottle. At the school that Ginny has chosen, Kit’s College, the blonde factor is sky high.

Sigourney Weaver reckoned that while she was in Galaxy Quest her IQ went down but Ginny insists Kit’s has a stiff entrance exam. I told her I assumed the first question is “Can your parents afford this?” but now, looking at all that hair I think question 2 must be “Are you blonde?” Girls who answer yes get in straight away and girls who take a long time to answer “no” get in as honorary blondes. Either way they marry well.

My daughter doesn’t think that funny.