The impact Southgate has had on the performance of England as a team should not be underestimated. Four tournaments, one quarter final, one semi final and two finals, that's incredible compared to what came before it and Southgate should rightly be lauded as one of the best England managers.
The question is what happens next. I doubt he will stay but if he did then I'd hope for some tactical evolution, maybe even extending his coaching staff to include some new thinking.
If he doesn't stay then who's next and what happens next? In an ideal world a new manager builds upon the great work Southgate has does and is able to take us to the next level. The worst case scenario is that without Gareth England revert to type.
Graham Potter's name gets mentioned a lot. There is a lot to like about him, his ability to coach and develop a team tactically, but he is a man who needs time to evolve a team, it took him a while before Brighton were playing the way he wanted them to play (I believe it was the same at Swansea and obviously with time he might have turned things around at Chelsea although that team is such a mess you wonder if anyone could) and he'd have even less time with the team at international level.
Tuchel and Pochettino have been mentioned but I think England have gone down the "successful foreign manager" route before and it's rarely worked. In addition I could see someone like Tuchel tearing up the hard work Gareth has done to create a new team spirit within the England camp.
I've heard Lampard and Gerrard's names mentioned and anyone mentioning them needs to fuck off and keep fucking off. I don't want either of those lousy managers anywhere near England.
Lee Carsley is an interesting thought, and would be very much going down the Southgate route given he's been the U21 manager for the last three years and likely already knows many of the younger players quite well. His win ratio with the U21s is even better than Southgate's was as well.
Beyond these I think Eddie Howe would be a very good choice. An intelligent manager, good man manager and good tactician.
I think my top three would be Howe, Carlsey, Potter.