Three UK is a major UK telecommunications operator offering mobile, broadband, and fixed-line services to approximately 10.6 million customers. Founded in 2001 and headquartered in Maidenhead, it operates as a subsidiary of CK Hutchison Group.
The company competes in a highly regulated UK telecoms market dominated by larger players.
Founded 2001Head office Maidenhead, United KingdomStaff ~4,500Revenue ~£2.59BWebsite ↗
Three UK lacks entity-level emissions disclosure, relying entirely on parent company CKHGT's group-level data. Carbon footprint, supply chain, and trajectory evidence are absent at the operating company level. Strong renewable electricity commitment (97%) and SBTi-validated targets are offset by no biodiversity policy, minimal waste metrics, and no standalone sustainability reporting despite £2.59bn revenue.
Three UK scores 41/100 (Below expectations) on SINK's independent climate assessment, scored from public data only. Scores are free. Companies can never pay for anything about their own score. Last verified May 2026.
That places Three UK joint 384th of 934 companies scored, and 14th of 19 in Telecommunications.
Strongest on Controversies & Red Flags and Energy Source (8/10, 7/10). Weakest on Nature & Biodiversity Impact and Water Impact (2/10, 3/10).
For each question that lost points, the evidence our public rubric looks for that we didn't find.
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SINK = (0.3 × Base + 0.7 × Performance) × Scale9 sources used in this assessment. All publicly available. Each row shows which of the ten questions it informed.
56% of them were published by Three UK itself; the rest come from independent sources.
Scored on 4 April 2026 under an earlier version of our method. We're re-checking it under the current method.
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Where Three UK sits among telecommunications peers.
Among the 19 major telecommunications brands we've scored, Three UK sits 14th of 19.
The 3 companies in the sector scoring nearest above Three UK.
altafiber reports Scope 1+2 emissions with third-party verification and a 40%-by-2030 target, but Scope 3 (73% of footprint) is screened only once per 3–5 years with no supplier engagement.
See the breakdown →Airtel Africa discloses emissions data aligned with GHG Protocol but lacks third-party verification.
See the breakdown →BT Group discloses operational emissions comprehensively with third-party assurance and has achieved 52% absolute Scope 1+2 reduction.
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