Contrary to many other countries in the world, tenancy agreements in London and the UK are rather short-term oriented.
In London, the usual length is 12 months.
It is possible to have 24 or 36 months agreements, but they are less frequent and will usually include a “break clause after 12 months.
The aim is to give flexibility to tenants and landlords alike – landlords are used to a high tenant turnover.
In any case, the length of a tenancy has to be negotiated between the tenant and the landlord or the estate agent representing the landlord. There are no country-wide “standard” agreements, as regulations are very light in that respect.
It is therefore down to the tenant to make sure that, during the negotiation, his or her interests are expressed and taken into account by the landlord when drafting the tenancy agreement.