Hi, thanks for your question. It looks like the other expert is offline at the moment so if you require an urgent answer I'm happy to help you.
Pursuant to s.11 of the Landlord and Tenant Act 1985, the responsibility of a landlord includes ensuring that all heating and hot water installations are in a safe and working condition. This would include ventilation and flues and therefore if the chimney was in working use for heating purposes, it would require the landlord to carry out an annual sweep of the chimney. However, as it has been blocked with a chimney balloon, and is not used for heating, we also need to look at the tenant's maintenance obligations.
Tenants do have a duty to use the property in a "tenant-like" manner and must take proper care of it by being responsible for the small jobs that can reasonably be expected of him from his tenancy agreement. These can include unblocking drains, changing fuses, having chimneys swept etc. Nevertheless, subject to anything expressly to the contrary in the tenancy agreement, if the chimney is out of service and has not been used by the tenant, my view is that it would not be a task reasonably expected to be carried out by the tenant. He hasn't created the soot, so it shouldn't be his maintenance issue, if it becomes a problem that needs dealing with. On that basis, and considering the statutory obligations, this minor maintenance cost should probably be born by the landlord.
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