Legal Nuisance

A nuisance occurs when a person’s quality of life is adversely affected by another person’s act or omission.
Liability for nuisance can be in common law, in tort, or pursuant to statute.

Common law

At common law there are two types of nuisance – a public nuisance and a private nuisance.
A public nuisance occurs  when an act or omission affects the general public, and will rarely arise with regard to residential property. A private nuisance occurs when the act or omission of a person or persons adversely interferes with those in a neighbouring property. Nuisance is most likely to occur in common parts or in property that is nearby and is owned by the landlord.

Landlord’s duties
Two important covenants are implied into all tenancy agreements to protect the tenant, even in the absence of an express term. The landlord is under a duty to keep the structure and exterior of the premises in a state of repair (s. 11 Landlord and Tenant Act 1945) and would be liable for any nuisance caused as a result if the disrepair were allowed to continue after being informed of it.
All tenants also benefit from a covenant for quiet enjoyment, the main effect of which is, in practice, to protect a tenant against harassment and eviction by the landlord. However, the covenant for quiet enjoyment does not extend to activities outside the landlord's control such as noise from a neighbouring property, damage by third parties, or infestation by pests.
This means that the landlord can normally choose to refuse assistance where their tenant suffers damage or annoyance due to actions from adjoining occupiers or becomes involved in a dispute with neighbours. 
However, the landlord may find that he has no real choice but to intervene in order to prevent any damage to the property or simply to enable the property to be more easily let.

Tenant's Duties:
A tenant is obliged to take care of the property, and must ensure that neither his activities nor those of his visitors cause damage to the property or disturbance to those living nearby. 
If the tenant breaks this covenant, a landlord may rightfully apply to the court for possession.

Liability
Third parties – it is the occupier of property who is liable for any nuisance caused by the property. This means that the landlord has no duty of care in respect of nuisance caused by his tenants unless he has authorised the tenants’ actions/omissions; the tenant would be liable instead.
Where premises adjoining a highway (road) are out of repair in such a manner as to constitute a nuisance to the public and a passer-by or adjoining owner is injured, the tenant rather that the landlord or owner of the premises is liable for the injury. However, the landlord will be liable in nuisance to anyone injured while actually on the highway if he has contracted to do the repairs or has reserved the right to enter the premises to do the necessary repairs. Where injury is due to want of repair, the occupier or owner is liable whether or not he knew or ought to have known of the want of repair.
Landlord to tenant - A landlord may be liable in nuisance where he retains part of the tenanted building but allows this part over which he has control to fall into disrepair, or if he causes any interference with the tenant’s enjoyment of the tenant’s part.
The landlord will not be liable to a tenant for nuisance caused by another of his tenants, unless he has authorised the nuisance.
Landlords are not liable to tenants for the noise nuisance of another tenant which is due to a lack of sound-proofing between flats (unless they are liable under a repairing covenant for the lack of sound-proofing). 
Tenant to landlord – it is common for tenancy agreements to contain a general covenant prohibiting the tenant from ‘doing or permitting to be done at the property, any act which may be a nuisance, damage or annoyance to the landlord or to the occupiers of any of the neighbouring premises’. This is a common wide-ranging provision that covers a variety of ills. Pets are a frequent source of damage in rented property, so tenancy agreements will often contain a clause restricting the tenant from keeping pets at the property without permission.
A tenant cannot complain of nuisance due to the noises of ordinary life caused by another tenant of the same landlord, especially where nothing has changed during the currency of the tenancy.

Statutory nuisance

Nuisance is also a criminal offence, pursuant to s. 79 Environmental Protection Act 1990, and is dealt with by the council for the benefit of the community (s. 79(1)). Statutory nuisance investigations must be carried out with good evidence collecting procedures.
Statutory nuisance means ‘any premises in such a state as to be prejudicial to health or a nuisance’, and s. 79 limits this to:
a) any premises in such a state as to be prejudicial to health or a nuisance;
b) smoke emitted from premises so as to be prejudicial to health or a nuisance;
c) fumes or gases emitted from premises so as to be prejudicial to health or a nuisance;
d) any dust, steam, smell or other effluvia arising on industrial, trade or business premises and being prejudicial to health or a nuisance;
e) any accumulation or deposit which is prejudicial to health or a nuisance;
f) any animal kept in such a place or manner as to be prejudicial to health or a nuisance;
g) noise emitted from premises so as to be prejudicial to health or a nuisance;
h) any other matter declared by any enactment to be a statutory nuisance;

Whether statutory nuisance has been committed is decided by an authorised inspector, depending on the nature, severity, frequency and duration of the nuisance. If a statutory nuisance is proven, the council are obliged to serve an abatement notice requiring the person causing the nuisance to stop. If this person does not comply with the nuisance, they may be fined up to £20,000 per incident of non compliance.