186.—(1) This section has effect—

(a) despite the fact that the tenancy concerned is one for a fixed period, and

(b) despite anything to the contrary in the lease or tenancy agreement concerned.

(2) If a landlord of a dwelling refuses his or her consent to an assignment or sub-letting of the tenancy concerned by the tenant, the tenant may serve a notice of termination in respect of the tenancy and terminate it accordingly.

(3) The period of notice to be given by that notice of termination is—

(a) that specified in section 66, or

(b) such lesser period of notice as may be agreed between the landlord and the tenant in accordance with section 69,

even if the lease or tenancy agreement provides for a greater period of notice to be given.