If it is at breakfast time it will be something like kedgeree.

If it is at lunch or dinner time, it will be some sort of hot fish with pasta, rice or veg etc.

At other times it will be some kind of salad with salmon more often than not.

I see a lot of people order special meals and then see what other passengers are being offered and then change their minds and say they don't want their special meal. In cases like this, they can only have the normal option, if one of the other passengers does not want to eat, as in most cases BA flights are catered exactly.