If the tenants have stayed on after the end of the fixed term and the tenancy has continued as a periodic tenancy then you can increase the rent using what is known as a Section 13 Notice. The Section 13 notice can be found here under Form 3.
Rules for serving a Section 13 notice.
There are different notice periods depending on how frequently the rent is paid. If the rent is paid monthly which is usually the case then you are required to give the tenant one month's notice of the rent increase.
If the rent is paid annually then you must give 6 months notice and in all other cases the notice period must match the periods at which rent is paid.
When Can you serve the notice?
You cannot serve a S13 notice within 1 year of sending a previous notice
Can a tenant dispute the rent amount?
A tenant can challenge the proposed rent by applying to the First-tier Tribunal (Property Chamber) and asking them to determine the fair market rent. This must be done before the S13 notice takes effect.
Please note that the Section 13 notice can only be used in England. For information on how to increase the rent in Scotland or Wales please see the following articles: