Dangerous Dog!

Other

I have a tenant who signed a 12 month AST, the AST says no pets, she has been in the property for 4 months now and has bought a dog which she leaves out in the yard all day, when people walk past the house the dog snarls and barks at people walking past, I have told her to get rid of the dog as she does not have permission for which she told me to get lost, further, the dog has eaten away at the door casing to the back door and eaten the plastic fall pipe on the wall. The tenant is adamant she is not going to get rid of the dog, any ideas as to what to do with this tenant and the dog?

regards

Jason