giffgaff sustainability score: 58/100
Leading practice starts at 60. The highest score on SINK is 71.
giffgaff is a UK mobile network operator that runs on the O2 network and is a wholly owned part of Virgin Media O2. Incorporated in 2001, it has its registered office in Reading.
More about giffgaff
It had about 299 staff and revenue of £633.8m in FY2025.
Founded 2001Head office Reading, UKStaff ~299 (FY2025 accounts average)Revenue £633.8m (FY2025)Website ↗
giffgaff reports Scope 3 as 99.9% of its emissions, mostly the O2 network and purchased goods. Its market-based total fell 9% in 2025 to 34,518 tCO2e, above its 2023 figure. It says it began a review of its SBTi targets in 2025 because the baseline predates its broadband service. Its figures carry no external assurance. It reports that 66% of the devices it sold in 2025 were refurbished.
giffgaff scores 58/100 (Making progress) on SINK's independent climate assessment, scored from public data only. Scores are free. Nobody can pay to change a score, speed it up or hide it. Last verified November 2026.
That places giffgaff joint 25th of 1,023 companies scored, and joint 3rd of 19 in Telecommunications.
What is giffgaff doing well, and where does it fall short?
Strongest on Controversies & Red Flags and Carbon Footprint: Operations (8/10, 7/10). Weakest on Nature & Biodiversity Impact and Water Impact (4/10, 4/10).
Where giffgaff lost points
For each question that lost points, the evidence our public rubric looks for that we didn't find.
What would raise this score
- Its effect on natureMeasure its effect on nature and have it independently verified.
- Its effect on waterMeasure its water footprint and set reduction targets.
- Whether its emissions are fallingShow a year-on-year fall in its total emissions.
Every question that lost points
- Emissions from its own operations7/10Its own emissions aren't independently verified or tracked over several years.
- Emissions from its supply chain7/10No full value-chain map or supplier engagement programme.
- Whether its emissions are falling5/10No evidence of a year-on-year fall in its total emissions.
- How clean its energy is5/10Less than half its energy shown to be renewable, or no transition plan.
- Its effect on nature4/10Its effect on nature isn't measured or independently verified.
- How it uses materials and handles waste7/10No verified figures for reuse and recycling across the business.
- Its effect on water4/10No measured water footprint with reduction targets.
- Its climate targets5/10Its targets aren't science-based or committed to the Science Based Targets initiative.
- How openly it reports7/10No mission-locked structure, such as B Corp certification.
A score changes when the evidence does. We use new published evidence at the next rescore. Anyone can send us new evidence, free. How to send it.
How is giffgaff's SINK score calculated?
Same ten questions for every company. No private weighting.
SINK = (0.3 × Base + 0.7 × Performance) × ScaleHas giffgaff's score changed?
giffgaff's score has moved from 59 to 58 across 2 recorded reviews, down 1 point.
- 59 → 58-17 November 2026
Q8 lowered from 7 to 5: no row in the SBTi target file; the parent's validated targets earn no brand credit (owner ruling 2026-11-07, as Roblox).
- Scored 597 November 2026
Initial public score 59 (publish-draft)
What evidence is giffgaff's score based on?
13 sources used in this assessment. All publicly available. Each row shows which of the ten questions it informed.
31% of them were published by giffgaff itself; the rest come from independent sources.
9 of 13 sources are independent of the company.
“emissions have been calculated in line with the GHG Protocol”
“Full accounts made up to 31 December 2024”
“In 2024 our emissions increased by 13% compared to 2023”
“We cut our greenhouse gas emissions by 9% compared to 2024”
“These tariffs do not fundamentally affect the emissions impact of the UK’s mobile network infrastructure.”
“running their offices with 91% renewable energy (from 2023)”
“In late 2023, giffgaff and MG OMD established the Up To Good Fund”
“made our SIM packaging from 100% FSC accredited MIX paper”
“an error in their billing system led to around 2.6 million customers”
“Ofcom fined Brit MVNO Giffgaff £1.4m today”
“Secured validation of our near-term and net zero emissions reduction targets”
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How does giffgaff compare with other telecommunications companies?
Where giffgaff sits among telecommunications peers.
Among the 19 major telecommunications brands we've scored, giffgaff is tied =3rd of 19, with 1 other.
Who scores higher in Telecommunications?
The 2 companies in the sector scoring nearest above giffgaff.
KPN's emissions fell across all scopes in 2025, and it has SBTi-validated targets for net zero by 2040.
See the breakdown →Proximus cut its total emissions 15% from 2020 to 2025 and has SBTi-validated targets for net zero by 2040, but in 2024 it replaced its near-term targets with weaker ones and expects to miss its 2030 supply-chain target by 11%.
See the breakdown →Which companies moved this week, and why.
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