London’s office market saw 11.5 million square feet of take-up in 2025, which is 11% above the five-year average. That figure tells you something important right now: competition for the best office space is real, and it’s not slowing down. I’ve been watching commercial property trends for years, and what I keep seeing is that the businesses that plan ahead — sometimes 12 to 18 months before their lease ends — are the ones that end up in the right space at the right price. The ones who wait until the last minute often get stuck with second-best options or much higher rents.
The problem is straightforward: there isn’t enough high-quality office space to go around. Across the whole UK, there’s only about 1.3 years of supply currently under construction, according to CBRE’s market analysis. That means if you’re thinking about renting an office in 2026 or early 2027, you’re entering a market where the best buildings are being snapped up before they’re even finished. Here’s what you actually need to know.
Understanding the Office Market Squeeze
The most important thing to grasp is that this isn’t a temporary blip. The supply shortage is structural. Of the 5.9 million square feet of space completed across London in 2025, 70% was pre-let before construction finished. That means seven out of every ten new offices were already spoken for. Looking ahead, 44% of the 2026 development pipeline is already committed, including large requirements from tenants like Formula 1 and OpenAI.
What this means for you is simple: if you wait until your current lease is about to expire to start looking, you’ll be competing with everyone else who did the same thing — and the best spaces will already be gone. My advice is to treat your office search like a major project, not a quick errand. Start early, get professional help, and be prepared to make decisions faster than you might be comfortable with. If you’re unsure about the legal side of things, it’s worth understanding assignment clauses in UK commercial leases before you sign anything.
Why the Supply Shortage Affects Your Bottom Line
This isn’t just about having fewer options to choose from. The supply shortage has direct financial consequences. Prime rents in the City core grew by 9.1% in 2025, and in the West End core they jumped 18.8%, according to CBRE’s prime rental growth data. CBRE forecasts further growth in 2026, with City core rents potentially reaching £93.00 per square foot and West End core rents hitting £200.00 per square foot by year-end.
Consider this scenario: a business currently paying £80 per square foot in the City core for 5,000 square feet is looking at an annual rent of £400,000. If they need to renew or relocate into comparable Grade A space, they could be facing £465,000 per year at the forecast £93 rate — an extra £65,000 annually. That’s not pocket change for most businesses.
Regional markets aren’t immune either. CBRE forecasts prime rental growth between 1.0% and 5.3% across most UK cities in 2026. In some regional cities, intense competition for scarce Grade A stock could push top-end rents towards £55.00 per square foot — the level needed to justify new speculative development. What I tend to notice is that businesses based outside London often assume the supply problem is a capital-only issue. It’s not. The same dynamics are playing out in Manchester, Birmingham, Edinburgh, and other major cities.
One group feeling this more than others is the growing artificial intelligence sector. AI office requirements in London reached 0.7 million square feet by January 2026 — a 136% increase year-on-year, according to Colliers’ London Offices Snapshot. OpenAI and Anthropic are expected to sign major lettings early in 2026. That’s a lot of new demand piling into an already tight market. If you’re in a growth sector, you need to be even more proactive.
Where Businesses Get It Wrong When Renting Office Space
Waiting Too Long to Start the Search
The most common mistake I see is businesses starting their office search three to six months before their lease ends. In today’s market, that’s a recipe for disappointment. With 70% of new space being pre-let and the development pipeline already 44% committed, the available options at that stage are often the ones nobody else wanted. The fix is to start 12 to 18 months out. That gives you time to evaluate pre-let opportunities on buildings still under construction or refurbishment, which is where the best value and quality often sit.
Ignoring the True Cost of Fit-Out
Many tenants focus entirely on the headline rent and forget about fit-out costs. Increased fit-out and rental costs have been key factors driving occupier decisions to renew rather than relocate, according to CBRE. If you’re moving into a shell space, you could be looking at £50 to £100 per square foot just to make it usable. That’s £250,000 to £500,000 for a 5,000-square-foot office. A better approach is to look for “refitted” Grade A space where the landlord has already done the work, or to negotiate a landlord contribution to fit-out as part of your lease terms. You should also look beyond the rent at the hidden costs of UK commercial leases before committing.
Overlooking Business Rates and Service Charges
Rent is only part of the monthly cost. Business rates and service charges can add 30% to 50% on top of your rent. Many tenants don’t check the rateable value of a property before viewing it, only to discover later that the rates bill is unaffordable. The same goes for service charges — some buildings have high charges for things like concierge, security, and maintenance that you may not need. Always ask for a full breakdown of service charges and check the rateable value on the government’s website before you view. For a deeper look, read our guide on how to navigate business rates when renting in the UK.
Assuming Renewal Is the Easy Option
With new Grade A vacancy in the West End falling to just 1.4%, many tenants are choosing to renew or regear their existing leases rather than move. That sounds sensible, but it comes with risks. Landlords know you have limited options, so they may push for higher rents or less favourable terms on renewal. You also miss the opportunity to improve your space efficiency or relocate to a better location. If you do consider renewal, get professional advice and negotiate hard — don’t just accept the first offer.
→ Scroll right to see all columns
| Market | 2025 Prime Rental Growth | 2026 Forecast |
|---|---|---|
| City Core | 9.1% | Up to £93.00 psf |
| West End Core | 18.8% | Up to £200.00 psf |
| Regional Markets | 1.0% – 5.3% | Up to £55.00 psf top end |
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How to Secure the Right Office Space in a Tight Market
Start Your Search 12 to 18 Months Early
This is the single most important action you can take. With 44% of the 2026 development pipeline already committed and pre-lets dominating the market, the best spaces are being taken well before they’re advertised. Begin by identifying buildings under construction or refurbishment in your target area. Contact the developer or landlord directly to express interest. If you’re working with a commercial agent — and you should be — ask them to flag pre-let opportunities as soon as they become aware of them. The earlier you’re in the conversation, the better your negotiating position.
Consider Peripheral Locations for Better Value
CBRE notes that tight Grade A vacancy in core markets, combined with an increased focus on cost, is shifting many large occupiers’ requirements towards good quality space in more peripheral locations. This marks the end of the “flight to core” trend that dominated recent years. If you’re flexible on location, you can often find better quality space at lower rents just a 10- to 15-minute walk from the prime core. Areas like the South Bank, King’s Cross, and fringe City locations are seeing increased interest. The trade-off is a slightly longer commute for some staff, but the savings can be substantial.
Negotiate Fit-Out Contributions and Rent-Free Periods
In a market where landlords are keen to secure tenants for new developments, there’s still room to negotiate. Ask for a fit-out contribution — typically £20 to £50 per square foot depending on the building and lease length. Also negotiate a rent-free period while you fit out the space. Three to six months is standard for a new lease, but you may be able to push for more if you’re taking a larger space or signing a longer term. Don’t be shy about asking. The worst they can say is no, and many landlords expect these requests as part of the process.
Get Professional Legal and Surveying Advice
Commercial leases are complex documents with long-term financial implications. Don’t rely on your friend who “knows about property” or try to handle it yourself to save money. A good commercial property solicitor will review the lease for onerous clauses, check the service charge provisions, and ensure you understand your repairing obligations. A surveyor can advise on whether the rent is fair and whether the building is suitable for your needs. The cost of professional advice is small compared to the cost of a bad lease. If you need to speak with a specialist, consider using a tenant landlord lawyer who can review your lease terms before you sign.
Plan for the AI and Tech Sector Impact
This is an emerging angle that many tenants haven’t considered. London’s growing artificial intelligence sector is becoming an increasingly important source of office take-up, according to Carter Jonas. AI requirements reached 0.7 million square feet by January 2026, up 136% year-on-year. If you’re in a traditional sector like banking, legal, or professional services, you’re now competing for space with well-funded AI companies that are growing fast and willing to pay premium rents. This competition will only intensify through 2026 and 2027. Factor this into your timeline and budget — don’t assume you can wait and still get the same deal.
- 1Assess Your RequirementsCalculate your space needs, budget, and desired location. Factor in growth projections for the next 5 years.
- 2Engage a Commercial AgentFind an agent who specialises in your target area. They’ll have access to off-market and pre-let opportunities.
- 3Instruct a Solicitor EarlyGet a commercial property solicitor involved before you make an offer. They can flag issues in the heads of terms.
- 4Negotiate Heads of TermsAgree on rent, lease length, break clauses, fit-out contribution, and rent-free period before the full lease is drafted.
- 5Complete Due DiligenceCheck business rates, service charges, EPC rating, and any planned developments nearby that could affect the property.
Frequently Asked Questions
Can I still find good office space if I only have 3 months left on my lease? ▾
What’s the difference between Grade A and Grade B office space? ▾
Should I sign a pre-let lease on a building that hasn’t been built yet? ▾
How much should I budget for business rates on a new office? ▾
Is it worth looking at offices outside the city centre? ▾
Your Next Move
The UK office market in 2026 is defined by one thing: supply constraints. With only 1.3 years of construction pipeline, 70% of new space pre-let, and prime rents rising across every major market, the businesses that succeed will be the ones that start early, think flexibly about location, and get professional advice. Don’t wait until your lease is about to expire. Start your search now, consider peripheral areas, and negotiate hard on fit-out and rent-free periods. If this was useful, you might also want to read Essential UK Building Regulations Every Commercial Tenant Should Know.
Sources and Further Reading
Understanding Tenant Service Charges: Tips for Renting in the UK — A practical guide to what service charges cover, how to challenge them, and what to look for in your lease.
London Offices Snapshot January 2026. Colliers, 2026.
UK Real Estate Market Outlook 2026: Offices. CBRE, 2026.
Outlook 2026: London Offices. Carter Jonas, 2026.
