If the rent is consistently paid late or a tenant is 2 months in arrears, the landlord or their agent will serve a section 8 Notice (on the relevant grounds) seeking possession of the property through the courts. 

This is the last resort any landlord would like to take as the costs involved will be high and usually passed onto the party that loses the hearing. In addition, if possesion is granted, this will be passed onto other agents when they request a reference for any future rental.