As sunshine indicates, the mince pie is in the British tradition of mixing meat, fruit and spices. Back in Elizabethean times, it would almost certainly have had minced beef or lamb in it. Nowadays, the only meat content in the jars comes from the suet. I have tried the vegetarian “suet” versions and prefer the more common omnivore one
By the by, I’m also surprised that Robinson’s “Classic” mincement uses a vegetarian suet (label describes it as palm oil, sunflower oil and rice flour). I’ll be paying close attention to labels when I go shopping in a few days.