Is pig's fat considered as food in Britain?

Yes they do. They eat pork fat and pork cracking (crispy pork skin) around roasted pork. Some people cook in pork fat (called lard) and some people add it to cakes and pastry. Many pork products such as pork sausages and pork pies contain quite a lot of fat. People even spread pork dripping, that is the melted fat from roast pork, after it has cooled and set, on bread to eat.