A landlord, in very general terms, has a legal responsibility to repair the structure and exterior of the property, including drains, gutters and external pipes; to keep in working order the installations for the supply of gas, electricity and water; and, for the installations for the provision of space and water heating.
The landlord also has other legal responsibilities relating to the safety of such items as gas, electricity and furnishings as well as the general standard or fitness of the property for habitation.
A tenant has an implied covenant to act in a “tenant-like manner”. This means to report disrepair promptly; to take reasonable steps to ensure that neither the tenant nor guests damage the property, its fixtures and fittings; to do the minor day to day things any home-occupier would normally do e.g. replace light bulbs, fit a new battery in a smoke or CO2 detector, tighten an odd screw which has come loose on a door handle; to keep the property reasonably warm and aired to help prevent condensation or freezing of pipes; to leave the property secure when absent from it; to keep the garden and other areas reasonably tidy and free from rubbish.