Property inspection refused and locks changed

I have had the same tenant for four years. The tenancy agreement stated that no locks be changed without the landlords permission, but they have been changed and although I was promised that spare keys would be given to us, this has not happened.

Originally this was in the hands of an agent, but they found that the tenant would not comply to periodical inspections so I decided to manage the property myself. The rent is always paid regularly ( just a few days late now and then), but the problem is that I need to do an inspection as this has not been done for over two years.

Despite contacting the tenant via his mobile and sending a letter giving him two weeks to arrange a convenient time to allow entry to inspect the property he has completely ignored any attempt to arrange it. I have never increased the rent since he took up the tenancy.

I really need to inspect the property for the state of repair for insurance purposes. Should I have a set of keys and what is the way to get him to allow an inspection?

Any advice appreciated

Jemma