Tenants moving out and have arrears, but can I impound their property?

Tenancy Types and Management

I have tenants who stopped paying their rent 5 weeks ago, they have not responded to my calls and letters over last 5 weeks. Their tenancy runs until July 2007.

Today I visited the property and see that the tenants are in the process of moving out, some of their possessions are still in the house. I spoke with the neighbours who told me the tenants have moved to Scotland (over 200 miles away from here). So it look like they have moved, but will be back to collect the rest of their things.

My questions is: Can I remove some of their property in lieu of the rent arrears and damage they have done?

I'm worried that if I don't move fast, they will be gone in the next day or 2.

Will I be breaking the law?

As far as I'm concerned they have already left the property as it is clearly not been inhabited for several days (maybe even weeks), so I think I have a right to enter it, but not sure legally?