Renters' Rights Act 2025, Phase 1 commencement
Transition readiness pack

Commercial Lease Law

Open Market Rent Review UK — Commercial Lease Procedure and Evidence

An open market rent review resets the rent in a commercial lease to the prevailing open market rental value at the review date, assessed by reference to what a willing landlord and willing tenant would agree. Open market reviews are the most common type of commercial lease rent review in the UK. Review procedure: trigger notice (landlord); counter-notice (tenant); negotiation; referral to RICS arbitration or expert determination if not agreed. Time of the essence: generally not (United Scientific Holdings v Burnley BC [1978]) — missing trigger notice date does not bar the review but means new rent does not backdate. Assumptions: willing landlord and tenant; vacant possession; covenants performed; premises fit for use; new lease on same terms including review clause. Disregards: tenant's occupation; tenant's goodwill; tenant's improvements made with landlord's consent at tenant's cost. Upward-only: market standard — rent cannot fall below passing rent on review. Comparable evidence: RICS Red Book lease comparables adjusted for incentives; rent review settlements; arbitration awards. RICS arbitration: Arbitration Act 1996; RICS President appoints; award binding; limited appeal on law. Expert determination: independent expert; own judgment; binding; no appeal except fraud/manifest error. Scotland: similar principles; s.9 Law Reform (Miscellaneous Provisions) (Scotland) Act 1985 time of the essence rules.

10 min readUpdated 7 June 2026Last reviewed: 17 May 2026open-market-rent-reviewrent-review-procedureupward-only-rent-reviewrics-arbitration

Rent Review Procedure — Trigger Notices and Time of the Essence

Open market rent review procedure typically requires the landlord to serve a trigger notice proposing a new rent at or before the review date; the tenant serves a counter-notice to dispute. Time of the essence: under United Scientific Holdings Ltd v Burnley BC [1978] AC 904, rent review timetables are presumed not to be time of the essence unless the lease expressly so provides or the structure of the lease clearly implies it. A landlord who misses the trigger notice date is not normally barred from implementing the review later — but cannot backdate the new rent to the review date. Upward-only reviews: standard in most UK commercial leases — rent can never fall below the passing rent on review even if the open market rent has fallen. Scotland: s.9 Law Reform (Miscellaneous Provisions) (Scotland) Act 1985 similarly presumes rent review timetables are not time of the essence.

Assumptions, Disregards and Comparable Evidence

Assumptions: willing landlord and willing tenant; vacant possession; tenant's covenants fully performed; premises fit for use; new lease on same terms (including the same rent review clause). Disregards: tenant's actual occupation (tenant not penalised for being in situ); tenant's goodwill; improvements made by the tenant with landlord's consent at tenant's cost (prevents tenant from paying higher rent for improvements it has funded). Comparable evidence (RICS Red Book): surveyors must rely on the best available comparable evidence — actual lettings in the market; rent review settlements; arbitration awards. Comparables must be adjusted for differences in size, specification, location, terms, and incentives (rent-free periods, fit-out contributions) to produce a consistent net effective or headline rent comparison.

Frequently asked questions

What is an open market rent review in a commercial lease?+

An open market rent review resets the rent in a commercial lease to the prevailing open market rental value at the review date, assessed by reference to what a willing landlord and willing tenant would agree. It is carried out on the basis of assumptions and disregards set out in the lease and must be supported by comparable rental evidence.

Is time of the essence in a commercial rent review?+

Generally no. Under United Scientific Holdings v Burnley BC [1978], rent review timetables are presumed not to be time of the essence unless the lease expressly provides otherwise. A landlord who misses a trigger notice date is not barred from implementing the review later, but cannot backdate the new rent.

What is the difference between RICS arbitration and expert determination in a rent review?+

RICS arbitration is a formal process governed by the Arbitration Act 1996 — the arbitrator receives submissions from both parties and makes a binding award. Expert determination is an informal process in which the independent expert uses their own judgment; the determination is binding and can only be challenged for fraud or manifest error. Expert determination is typically faster and cheaper.

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