What is a tried and tested fox deterrent?

[AplineDaisies]

Bloomin fox is doing a big dump every night two feet from out back garden patio doors.
Our garden is nothing special.
What really works to stop the fox going around our garden?

My 11 year old Cavalier pined the fox that lives next door into a corner of our garden tonight and had to called back to allow it to escape back to its own garden. I'm willing to rent him out ;-)

thanks, had no idea!