Is it morally acceptable to eat intelligent animals? Everyone can make their own mind up about this. Some people think that there's nothing wrong with eating any kind of animal. For me, I drew a somewhat arbitrary zoological line in the sand and decided that any animal "above" a fish was off-limits. In other words, birds and mammals are off the menu, whereas fish and invertebrates are OK to eat.

For the most part, this has served me pretty well. As Nirvana frontman Kurt Cobain put it, "it's okay to eat fish, cause they don't have any feelings." And I didn't mind eating prawns from a welfare or intelligence point of view.

But there was a problem: cephalopods. Octopus and squid are invertebrates, so following my "rule" they were perfectly acceptable for me to eat. However, their lack of a skeleton does not mean they lack intelligence — far from it. Octopus and squid — and cuttlefish, which are also cephalopods — are some of the most intelligent of all animals, and that includes dolphins, crows and apes. I brushed these concerns under the carpet and carried on eating them.