Who does this Burrow belong to?!

I have recently discovered a burrow in the garden and we are unsure of what animal it could belong to.

It is fairly close to our tree and looks like it burrows underneath our fence and under the neighbours shed.

The burrow is roughly 16cm in length and 10-13 cm in width.

My initial thought is that it is too small for a fox or badger but too big for mice or rats.

Do you have any ideas of what it could be?