By Fraser Williams, Director, Morgan Pryce
Up to 50 million sq ft of London office leases expire between now and 2030, while several core submarkets have under 15 months of available supply. Occupiers should now begin their property strategy 18–24 months before lease expiry as a minimum — and larger occupiers are committing an average of four years ahead.
A Supply Squeeze Meeting A Demand Wave
Two numbers explain the next four years of the London office market.
The first: up to 50 million square feet of London office leases are due to expire between now and 2030. Every one of those expiries is a business that must renew, re-gear or relocate.
The second: several of London’s most sought-after submarkets — Marylebone, Soho and the City Core among them — currently have less than 15 months of supply remaining. New development will not ride to the rescue: construction starts remain below trend due to planning constraints, elevated build costs and expensive development finance, with only around 1.3 years of Grade A supply under construction across the whole UK. In Central London, roughly 70% of 2026’s scheduled completions were pre-let before the year even began.
A wave of demand is about to hit a market with almost nothing on the shelf.
What This Does To Occupier Behaviour
The market has already responded. Organisations requiring more than 100,000 sq ft now commit to space an average of four years ahead of lease expiry, up from under three years in 2022. Pre-letting — once the preserve of banks and law firms — is spreading down the size bands as occupiers compete to secure operationally suitable buildings before rivals do.
For the SME occupier, this creates a dangerous asymmetry. The corporates have professionalised their timing. Many smaller businesses still treat the office as something to think about “when the lease is nearly up.” In this market, that habit hands all the leverage to the landlord.
The Cost of Waiting
Delay carries three compounding costs:
1. Price: Prime rents rose 9.1% in the City core and 18.8% in the West End core in 2025, with above-inflation growth forecast across all prime UK markets in 2026. Every quarter of delay is negotiated against a higher benchmark.
2. Choice: With around 70–80% of take-up concentrated in Grade A space and prime West End vacancy under 2%, the good buildings go under offer quickly — increasingly before they are widely marketed. A compressed search means choosing from what is left, not what is best.
3. Leverage: A landlord who knows you have run out of time to move will price your renewal accordingly. The single biggest determinant of renewal terms is whether the occupier has credible, evidenced alternatives — and alternatives take time to develop.
The 24-Month Playbook
For a typical SME requirement (2,000–20,000 sq ft), the timeline we recommend:
- 24 months out — strategic review: headcount projections, working patterns, budget envelope, renew-vs-relocate appetite.
- 18 months out — market search live; shortlist buildings; open a parallel dialogue with the existing landlord.
- 12 months out — heads of terms on the preferred option; use competing proposals as negotiation leverage whichever route you choose.
- 9–6 months out — legals, design and fit-out planning (fit-out lead times have lengthened alongside costs).
- Expiry — move or re-signed, with no cliff-edge and no forced hand.
The Opportunity Hiding in The Squeeze
It is not all defensive. The same market that punishes late movers rewards early ones. Landlords with space completing in 2027–2028 are hungry for pre-let commitments and will negotiate meaningfully for certainty. Secondary buildings undergoing quality refurbishment offer genuine value for occupiers prepared to look past the obvious postcodes. And occupiers whose leases expire after the 2028–2030 crunch can re-gear now, on today’s terms, before the expiry wave inflates the market around them. Timing, in this market, is not a detail of property strategy. It is the strategy.
Sources & Trend Proof
1. K2 Space / Knight Frank data, London Office Market Review 2026 — up to 50m sq ft of London lease expiries by 2030; under 15 months of supply in Marylebone, Soho and the City Core; large occupiers committing ~4 years ahead of expiry.
2. CBRE, UK Real Estate Market Outlook 2026 — Offices — 1.3 years of supply under construction UK-wide; construction starts below trend; 2025 prime rental growth of 9.1% (City core) and 18.8% (West End core); above-inflation prime rental growth forecast for 2026.
3. The Langham Estate, London Office Market Report — ~1.2m sq ft of new completions forecast for 2026 (down ~40% year-on-year); ~70% of 2026 completions pre-let; prime West End vacancy below 2%.
4. Carter Jonas, London Offices: The Outlook for 2026 — rising share of requirements met through pre-lets; footloose occupiers bringing searches forward as available Grade A supply declines.
FAQs
A minimum of 18–24 months for most SME requirements. Occupiers over 100,000 sq ft are now committing an average of four years ahead of expiry.
Construction starts are below trend, only around 1.3 years of supply is under construction UK-wide, and roughly 70% of 2026 London completions were pre-let before delivery. Demand is concentrated on the best space while the pipeline shrinks.
Not at the prime end. Above-inflation prime rental growth is forecast across UK markets in 2026, though older buildings with weak sustainability credentials may see rents stay flat or soften.
You typically default into a renewal negotiation with no alternatives — the weakest possible negotiating position — or a rushed relocation at whatever is available.
