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Updated 29 October 2026 · from filed accounts

The biggest construction companies in South East

Keltbray Built Environment is the biggest company among the construction companies registered in South East by turnover, with £320m in its latest filed accounts. RGCM and Atlas FM follow. Together the 10 companies below turned over £1.86bn in their latest filed years.

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  1. 1
    Keltbray Built Environment

    Thames Ditton · Building & construction · FY to Oct 2025

    £320m

    -12% on the year before

  2. 2
    RGCM

    West Malling · Building & construction · FY to Dec 2025

    £289m

    -7.8% on the year before

  3. 3
    Atlas FM

    Datchet · Building & construction · FY to Dec 2025

    £191m

    +43% on the year before

  4. 4
    Atlas FM Payroll

    Slough · Building & construction · FY to Dec 2025

    £183m

    +69% on the year before

  5. 5
    Riddingtons Cis & Payroll Solutions UK

    Swanley Village · Building & construction · FY to May 2024

    £170m

    +11% on the year before

  6. 6
    Seko Logistics (London)

    Windsor · Building & construction · FY to Dec 2022

    £150m

    +11% on the year before

  7. 7
    Atlas Cleaning

    Slough · Building & construction · FY to Dec 2024

    £148m

    Turnover

  8. 8
    Kellogg Brown & Root (U.K.)

    Leatherhead · Building & construction · FY to Dec 2025

    £147m

    -2.5% on the year before

  9. 9
    Knights Brown Construction

    Hampshire · Building & construction · FY to Mar 2026

    £136m

    +17% on the year before

  10. 10
    Sexton Holdings

    Littlehampton · Building & construction · FY to Dec 2025

    £128m

    +0.9% on the year before

How this list is made

From each company's latest accounts filed at Companies House, or its annual report for listed groups: the figures as filed, nothing estimated. Changes compare the two latest filed years. Only companies that report in pounds are ranked; groups that report in dollars or euros aren't converted. Subsidiaries whose figures are part of a listed group's are counted once, in the group. Updated daily as new accounts are filed.

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