Exclusive possession means that the tenant must have full possession of the landlord’s rental property and have exclusive use of, or, part use of that property. This allows the tenant to enjoy the use of the property uninterrupted for the term of the lease provided the tenant adheres to the terms and conditions specified in the lease. (Always refer to the terms of the lease.)
Within that it is normal for the landlord to make regular inspections of the property and the tenant must allow access for this, for workmen to make any repairs that are the landlord’s responsibility that might be needed, and for the landlords to show the property to prospective new tenants when the tenancy is in its notice period. The lease should make mention of this.