“Mrs Hudson has told me about a good game for the children to play at the Christmas party,” Dr Watson began. “It’s called ‘Fish’.”

“I hope there is no actual water involved,” Sloth muttered.

“Oh no, there’s no need to worry.”

At this point everyone looked fixedly at Ferret, who had been trying to impress his latest girlfriend by trotting nonchalantly through a puddle, only to find it had been rather deeper than he expected. He’d emerged, very wet, and to hear the little weasel giggling as she left.

“We begin,” Watson continued, “by having the children sit round in a circle. The leader then goes round the circle, tapping each child in turn and saying, ‘Cod, Plaice, Haddock’, so that by the end each child is called one of three names.”

“But why those names. Why not Ferret?” Ferret protested.

“Because ferrets are not fish,” Aemelia Vole replied.

“Well, then, Sloth. He can swim.”

“For the purpose of this game,” Watson said firmly, “we are using standard fish names. Then, the leader calls out cod, or plaice, or haddock, and all the children with that name stand up and start to run round the circle. They keep running until he calls ‘Fisherman’s coming’, at which point they have to run as fast as they can to sit in their own space. They must keep going in the same direction, no turning the other way.”

“Very sensible,” Poley the Moley said, “otherwise they’d be crashing into each other.”

“The last one back is out. And another fish is called. The game continues until there is only one fish left.”

“But surely there’d be one of each type,” Mouselet said.

“That’s when the other rules come in. The first rule is that if the leader calls ‘All fish’ all the uncaught fishes run round. And secondly, which can help some of the slower ones, the leader can call ‘Tide’s turning’, in which case they all turn round and run the other way. They’re not allowed to change direction until the tide turns again.”

“Very clever,” Ocelot said. “So if they’re almost back to their space they have to run all the way round again.”

“Exactly. What do you all think?”

Everyone thought it was a great game and that the children would enjoy playing. And no-one thought it was necessary for Ferret to demonstrate.