Troublesome tenants

New tenants just moved into a house 2 weeks ago - As Landlord, I'm starting to get calls from neighbours claiming that the new tenants are noisy, abusive and are apparently known criminals - one caller claims that the police have been called on a number of occasions! Anyone know the best way to deal with this?

Serve the tenants with notice to quit citing anti-social behaviour

And what's the position if they refuse to give vacant possession of the house?

PRTB, solicitor's letters, court, whatever legal measures and recourses are open to a landlord. You have responsibilities to rectify the situation if the allegations have foundation, whether you have access to appropriate supporting tools is a different matter entirely.