There are 2 legal ways to increase your tenant's rent. One is much simpler than the other. The simple way is to issue a new paper tenancy agreement (AST) at the new rent. Once the tenant signs this then it is a done deal. Unsurprisingly this is the method most landlords use.
The second way applies when your tenant is outside of a written tenancy, rolling from month to month on a statutory periodic tenancy and when you don't want to issue a new tenancy for whatever reason (maybe to avoid having to pay fees to protect or re-protect a deposit in the deposit protection scheme for example). In this case you must complete a specified rent increase notice, called a Section 13. A free Section 13 notice is included with the free tenancy pack we give to all our customers. The rent increase notice must give the tenant a month's notice before the new rent starts in order for them to be able to dispute the increase if they wish, which leads nicely into discussing rent amount disputes.
A tenant has the right to dispute the rent in a tenancy agreement or in a Section 13 rent increase notice. With the Section 13 they must file their dispute before the notice expires. The tenant can refer the rent to a rent assessment committee, who will decide if they think the rent is too high. The committee can – amazingly enough - actually force you as a landlord to lower the rent, regardless of whether the complaining tenant happily signed the agreement in the first place. On the flip side the committee could raise the rent if they think it is too low, but we've never come across a case where that happens.
Thankfully private tenants that complain to rent assessment committees are rare, probably because you can just serve a section 21 notice and get your property back if they upset you. For more information on this, and why it is a good idea to serve a section 21 at the beginning of a tenancy, see our related article and frequently asked questions section.