Hello and thanks for using Just Answer.
My name is ***** ***** am happy to assist you with your enquiry.
I am afraid that a Landlord can insist that both occupiers of a property be joint tenants. In certain circumstances, a Landlord can agree for the Tenancy to be in the sole name of one party, with the other occupier being a "permitted occupier". However, they can not be forced to do this, as a Tennacy agreement is a Contract, drawn up by the Landlord and he has the last word on what is and what is not permitted (subject to him complying with legislation).
There is no legislation stating that a Landlord has to allow a "permitted occupier" and nearly all Landlords will insist on all occupiers being Tenants, as it is easier to get an eviction, where you have a Tenant as opposed to a permitted occupier(the process is quicker), in the unlikely event of you defaulting on the payment of rent or one of the other Tenancy terms.
I am sorry this is not the answer you were looking for, but it sets out the legal position.