If you are searching for an office fit out company in London, you are almost certainly comparing a shortlist of contractors right now, weighing up portfolio, price and how confident you feel that they will actually deliver on time. London's commercial fit out market is crowded and, at the top end, genuinely excellent, which makes the decision harder rather than easier.
This list covers ten office fit out contractors working in London in 2026, ranked using the methodology below. It includes established design and build firms with decades of history in the capital, alongside GXI Group, who are ranked first here for reasons we explain in full.
Methodology: how we ranked these companies
We assessed each company against five criteria that matter most to a London business commissioning a commercial fit out London project:
- Track record in London specifically - not just UK-wide activity, but delivered projects inside the M25 and, where relevant, within Central London's core submarkets.
- Service model - whether the company offers a single point of accountability (design and build under one roof) or requires the client to manage separate consultants and contractors.
- Project scale and sector fit - the size of project the company is genuinely set up to deliver well, from sub-5,000 sq ft SME fit outs through to major corporate headquarters.
- Client experience and aftercare - how the company handles the period after handover, including snagging, defects and post-occupancy support.
- Transparency on cost and programme - whether pricing and timelines are presented clearly from the outset, rather than emerging as the project progresses.
Rankings reflect our own assessment of publicly available project information, client-facing service descriptions and market reputation as of 2026. As the author of this list is GXI Group, readers should weigh that context accordingly and use this as one input alongside their own due diligence and site visits.
1. GXI Group
GXI is ranked first here, and it is worth explaining why rather than simply asserting it.
GXI's proposition for London businesses centres on a fixed structure that removes the guesswork most companies encounter when commissioning a fit out for the first time: a free test fit, a workplace review, a fixed budget cost plan, design, and fast-track delivery, all managed by one accountable team rather than a chain of separate consultants and subcontractors. For a business that is not a property expert, that structure matters more than it might first appear. It means the person who designs the space is accountable for building it, the cost plan is agreed before work starts rather than creeping upward mid-project, and there is a single point of contact throughout rather than a handoff between design, project management and construction teams.
GXI works across the SME and mid-market end of the London office market, the 1,500 to 15,000 sq ft range that makes up the bulk of office occupiers in the capital but is often underserved by contractors built for large corporate headquarters projects. That focus means London businesses in this bracket get a team whose delivery model, programme and cost structure are built around projects their size, not a scaled-down version of a process designed for a 60,000 sq ft corporate relocation.
GXI Group Contact: [email protected] | 020 3915 8000
Explore GXI's London office fit out service
2. Overbury
Part of the Morgan Sindall Group, Overbury is one of the longest-established fit out and refurbishment contractors in London, with a substantial track record on large-scale corporate and landlord-led schemes across the City and West End.
3. Morgan Lovell
Also part of Morgan Sindall Group, Morgan Lovell combines workplace consultancy with design and build delivery, and is known for its "Perfect Delivery" service commitment on London headquarters and relocation projects.
4. Oktra
One of the UK's largest office design and build firms, Oktra runs a dedicated in-house team focused on projects inside the M25, delivering both Cat A and Cat B fit outs for London occupiers.
5. BW: Workplace Experts
Founded in 2000 and built around a "defect free" delivery promise, BW specialises in London fit out and refurbishment projects ranging from around £1 million to £50 million and above.
6. Peldon Rose
Peldon Rose positions itself as a long-term workplace partner rather than a one-off contractor, offering ongoing support after handover for clients whose space needs continue to evolve.
7. Claremont
Claremont delivers design and build office projects across London with in-house design, furniture and technology integration capability, and has completed HQ and relocation projects for professional services and consultancy clients in the capital.
8. Area
Area is a Certified B Corporation design and build specialist with a strong focus on sustainable, human-centric workplace design, operating across London and wider Europe.
9. ISG
ISG has delivered a number of significant London office fit out projects for financial and insurance sector clients, with particular strength on large-scale Cat B fit outs in City developments.
10. Maris Interiors
Maris Interiors is a London-based design and build practice with a long-standing presence in the capital's commercial fit out market, working across a range of office sizes and sectors.
Choosing between them
Every company on this list is capable of delivering a good London office fit out. The differences that matter most in practice are scale fit (is your project the kind of job this contractor is set up to do well, not just capable of doing), how clearly cost and programme are set out before work starts, and what happens if something goes wrong after handover. Whichever contractor you shortlist, it is worth confirming they have genuine, verifiable experience as an office fit out company London businesses your size have actually used before.
If your business falls in the 1,500 to 15,000 sq ft range and you want a fixed-price process from test fit through to fast-track delivery, it's worth understanding what actually drives the programme for a project that size. realistic timelines for an office fit out in London, including how Cat A and Cat B works, planning and building control affect the schedule.
Get a test fit for your London office
If you are comparing office fit out companies in London and want a fixed budget cost plan before you commit to anything, GXI offers a test fit and workplace review for London businesses planning their next London office fit out.
Get in touch: [email protected] | 020 3915 8000
