Under the current rules a rent increase is a once-a-year, formal event: Form 4A, two months’ notice, one increase per twelve months. Old contractual review clauses do not operate. And a tenant who disagrees can take it to tribunal for £47, with no hearing fee.
That combination changes the calculation. The increase is now visible, singular and easy to contest — which means the number needs to be defensible rather than optimistic.
Start from what the property would let for today
The tribunal’s test is market rent: what this property, in this condition, in this location, would achieve if it were advertised now. Not what you need to cover the mortgage. Not what it achieved in 2024. Not what the refurbished one on the next street is asking.
So the work is comparables. Three or four properties, same area, similar size and type, similar condition, actually let within the last few months rather than sitting unlet at an aspirational asking price. Write down addresses, dates and rents. That document is your entire case, and it takes twenty minutes.
Be honest about condition
This is where landlords most often talk themselves into a number that will not hold.
A property with the original kitchen, tired decoration and a D-rated EPC does not command what the equivalent floorplan with a new bathroom and an EPC of C does — even on the same street. Tenants can see the difference and so can a tribunal. If your property has not had anything done to it in eight years, the market rent reflects that, and pushing past it invites a challenge you will lose.
The flip side is genuinely useful: if you have invested — new boiler, insulation, redecoration — say so, and evidence it. Improvements justify increases in a way that inflation alone does not.
Consider what winning actually costs
Say you push for £75 a month above what the evidence supports. Best case, the tenant accepts and you are £900 a year better off. Worst case, they challenge, the tribunal sets a lower figure, you have lost the increase and gained a tenant who now regards you as someone who tried it on.
And under periodic tenancies you cannot easily end that relationship. There is no fixed term running out. You are in it for as long as they want to stay, which may be years.
A slightly smaller increase, evidenced, explained in a short covering note, accepted without friction, is very often the better commercial outcome — not because it is nicer, but because it is worth more over five years.
The practical sequence
Gather comparables. Sanity-check against condition. Pick a number you could defend to a stranger. Serve the correct notice, correctly, with the right period. Include a brief, plain explanation of the reasoning — not required, but it materially reduces the number of tenants who challenge simply because a bare form landed on the mat.
Most disputes are about surprise, not money.
From the tenant’s side of the table: what it costs a tenant to challenge your increase — useful to know, because it tells you how likely a challenge actually is.
General information, not legal advice.
Need a second opinion?
We’re Property Lounge, an ARLA Propertymark accredited lettings agency in Guildford. If anything above raised a question about your own property, we’re happy to talk it through — whether or not you’re a client, and whether or not you ever become one. No charge, no obligation, and we won’t chase you afterwards.
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