How can I deter Badgers?

They are immensely powerful ! You need a chain link fence more than 125cm high and dug down to perhaps 50cm into the ground with a piece at the bottom set at right angles facing outwards from the garden for a distance of about 50cm underground. Gateways and other points of entry need to be secure to stop badgers squeezing through or climbing over and under. It is expensive, but worth it.