Unfortuately no animals are allowed anywhere on board a BA aircraft, unless of course a service dog. I don't believe any UK airline will allow an animal in the cabin - they must all go in the hold.

Be very careful of quarantine restrictions too before thinking of taking a dog on your travels. They need a pet passport, vaccinations, and all kinds of things to be sorted before they travel ..... in the hold.

We used to accept dogs for travel at check-in but this was stopped about 2 years ago.

Mind you, a true story from about two years or so ago. We were frantically busy with massive queues at check-in when a colleague was checking in some Italian passengers. Bags were tagged and about to be sent when a yelping sound was heard. The lady tried to hide her hand baggage from where the yelping was coming from but was asked what she had in there. All of a sudden out popped ....... a Yorkshire Terrier, complete with bows and ribbons in its fur!!!!
Obviously she couldn't take it with her and the poor thing had to go to the Animal Reception Centre and subsequently had to spend 6 months in quarantine as it had been brought in illegally.
The security questions for the rest of that day were: Could anyone have interfered with your baggage; has anybody given you anything to take on board; and do you have any dogs in your hand luggage

Seriously though, far better for the pup to stay at home.