This is the problem when it come to pest control, arguably this becomes landlords responsibility under HHSRS https://www.pims.co.uk/the-29-hazard-specified-in-hhsrs/
(C )Protection against Infection - Domestic hygiene, Pests and Refuse
Unless due to tenant lifestyle – in which case they are liable – but this would be determined by pest controller
The government guidance is complicated see the guide Housing Health And Safety Rating System - HHSRS
This covers rodents
The design and construction should reduce, so far as is possible, any means of access
by pests from the outside into the dwelling. All openings into drains should be sealed
with an effective water seal; this includes openings such as into the wc basin and
drainage inlets for waste and surface water. To prevent mice entering there should be
no holes or gaps in excess of 6.25mm. Service entry points should be effectively sealed
as should any points in walls penetrated by waste, drain or other pipes or cables. There
should not be any holes through roof coverings, eaves and verges which might allow
access into the roof space of rats, mice, squirrels or birds. Any necessary holes for
ventilation should be covered with grilles.
Example tenant lifestyle
15.15 Poorly stored food waste will attract pests including flies, cockroaches, ants, wasps,
mice, rats, birds, foxes, squirrels, cats and dogs. Some of the insect pests may use the
waste for harbourage, as a site for egg-laying and development of larval stages, and all
can be vectors for pathogenic organisms which may breed in the food-associated waste.
These pests may then come into contact with food before it is prepared or eaten or
may come into direct contact with persons. Unless properly disposed of, the potential
dangers from household waste will increase as pathogenic organisms multiply. In
addition, the waste will become a source of smells.
Immigration Act revised 2016 should a landlord or letting agent fail to ensure ALL tenants/occupiers have a righto reside for the duration of the tenancy then they may be fined £3000 for each breach. The Secretary of State may instruct the landlord to remove such persons without the need of a court order by way of reasonable force
Labour market enforcement - restriction on illegal migrants to work. A labour market enforcement undertaking (an “LME undertaking”) is an undertaking by the person giving it (the “subject”) to comply with any prohibitions, restrictions and requirements set out in the undertaking
Under section 42 of the County Courts Act 1984 it is possible for the Court to transfer a matter from the County Court to the High Court for enforcement but leave (permission) of the Court is required first. The transfer time varies from court to court and can take up to 28 days, but normally takes far less. An application to seek permission can be made either at the time of making the possession claim or after possession has been ordered.