Bird in Tesco! But what is it?

Hello! I’m new here, and I didn’t know which forum to put this in. But I saw a bird in Tesco today, and was flummoxed by what it could be. It was like a robin but grey and black. Googling it suggests that it could be a black redstart, but I’m in the Midlands and they don’t seem to be found here? Any other ideas? sorry for the awful photos!