I dont really understand why your sister is still receiving the housing benefit after all this time of rent arrears. The council should have been informed immediately she was 2 months in arrears when the LA would have stopped payment to her and paid the landlord direct. If she is on LHA she only had to be 2 weeks behind for it to be stopped and then new arrangements made. Anyway your concern is your duties and obligations as guarantor. Basically it is down to the landlord to do the eviction etc and down to you to pay any outstanding rent and any damages bills there may be when she is removed from the property. As a tenant for approx 22 years I have made it my business to be 'up' on the different changes to the law on tenancy matters. Your sister sounds like the kind of tenant who gets all others a bad name. I'll bet she is the first one to put the landlord down too, as a 'fat cat'. Very sad. I hope you will think twice in future before you sign anything on her behalf. Sister or not times are tough and even family (close family) can screw you over without a second thought. What a sad world this has become.