“It’s not something that you would buy at Sainsbury’s.” (Why mention Sainsbury’s? Because there is a huge branch directly across the road from the school).

“Sainsbury’s is very expensive, sir.”

”Is it? Well, I was just using it as an example of a supermarket.”

My qualification of my comment came too late. There ensued some seconds of debate worthy of a noisy House of Commons. Lidl and Aldi and Morrisons were mentioned as places that were cheaper. Tesco has its adherents. One girl declared, “we shop at Waitrose.”

The conversation was both annoying and impressive – at that age I would have had little idea of the difference in prices between retailers, but I was trying to teach a lesson on Sikhism.

”Three, two and one and quiet. Thank you, Year 8. We’re not talking about supermarkets, we’re talking about what Sikhs wear.”

There was a look of disappointment on some of the faces, the robust discussion of supermarkets could clearly have continued for some time. I resumed the lesson but wished I had had a copy of Winnie the Pooh stories  to hand. We clearly wanted to talk about different things, as did Owl and Pooh the day that Christopher Robin led them on an ”expotition” to the North Pole.

“They had come to a stream which twisted and tumbled between high rocky banks, and Christopher Robin saw at once how dangerous it was.

“It’s just the place,” he explained, “for an Ambush.”

“What sort of bush?” whispered Pooh to Piglet. “A gorse-bush?”

“My dear Pooh,” said Owl in his superior way, “don’t you know what an Ambush is?”

“Owl,” said Piglet, looking round at him severely, “Pooh’s whisper was a perfectly private whisper, and there was no need – ”

“An Ambush,” said Owl, “is a sort of Surprise.”

“So is a gorse-bush sometimes,” said Pooh.

“An Ambush, as I was about to explain to Pooh,” said Piglet, “is a sort of Surprise.”

“If people jump out at you suddenly, that’s an Ambush,” said Owl.

“It’s an Ambush, Pooh, when people jump at you suddenly,” explained Piglet.

Pooh, who now knew what an Ambush was, said that a gorse-bush had sprung at him suddenly one day when he fell off a tree, and he had taken six days to get all the prickles out of himself.

“We are not talking about gorse-bushes,” said Owl a little crossly.

“I am,” said Pooh.

I wasn’t talking about supermarkets, they would have liked to have done so.