Joint honours a disadvantage for oxbridge masters?

I know it's a long way off but it's just out of pure interest. Are your chances of getting onto a History Masters at Ox or Cam decreased if you only have a joint honours in History? It would hopefully be a degree from Cam but not sure that's going to give me any extra brownie points should I ever want to so this. Just looking for an honest answer. Don't mind too much if it's a big disadvantage, but if it isn't, great! lol.