Procurement with purpose: How the City of London Corporation is cutting carbon through smarter data

The City of London Corporation is transforming how it measures and manages  its scope 3 purchased goods and services (PG&S) emissions. Through its Climate Action Strategy, the City Corporation is shifting from spend-based emissions calculations to more accurate, supplier specific data. This approach is embedded across procurement, contracts, and supplier engagement, enabling more targeted and effective climate action.

Historically, the City Corporation calculated PG&S emissions using spend-based factors - multiplying financial spend by carbon conversion factors. This method implied the only way to reduce emissions was to reduce spending, which limited strategic action. Additionally, the lack of granular data made it difficult to identify high-impact opportunities for carbon reduction across the supply chain.

The City Corporation introduced a three-pronged approach:

• Data collection: Moving beyond spend-based calculations, the City Corporation began collecting supplier-specific and contract-specific emissions data from 22/23. Suppliers were asked to provide their organisational carbon footprint and turnover, or emissions data directly linked to contracts. For data quality reasons, not all supplier data received is included, spend-based data is retained where supplier reported footprints do not include purchased goods and services emissions – this category typically accounts for about 80% of an organisation’s carbon footprint. In 2024/25, the City Corporation contacted 60 suppliers - primarily selected based on spend - and received responses from 40. This enabled more accurate emissions calculations for nearly 50% of PG&S spend.
• Procurement & contracts: Responsible procurement requirements are embedded into specifications and tender processes. Standard wording from our Climate Action toolkit - one of six Responsible Procurement Commitment toolkits - is incorporated into contracts, with officers selecting the appropriate wording and tender questions. The Climate Action wording requires suppliers to deliver low whole life carbon goods and services, and to demonstrate year‑on‑year sustainability improvements. Suppliers are also required to provide annual carbon reporting. The inclusion of these standard metrics is monitored and recorded internally on an annual basis.
• Supplier engagement: Active collaboration with suppliers and contract managers by email, contract meetings or dedicated responsible procurement meetings, ensures delivery of climate commitments and identification of further carbon reduction opportunities. In 2025 we held an event to show our suppliers the impact and benefit of reporting data to us. 

The shift in methodology is beginning to show tangible results, with emissions now decoupled from spend levels. 

The PG&S carbon footprint decreased by 21 per cent in 2024/25 compared with the previous year, despite an increase in overall spend. Since the baseline year (2018/19), this represents a 32 per cent reduction. Supplier-specific and contract-specific data generally resulted in lower emissions figures than spend-based estimates, although in four cases emissions increased - highlighting the value of accurate data to ensure effort is directed to the highest impact areas.

The City Corporation is committed to continuous improvement in data accuracy and transparency. Key next steps include:

• Ongoing supplier engagement to refine emissions data and identify reduction opportunities.
• Internal visibility enhancements, enabling contract managers and budget holders to view emissions linked to their contracts and cost centres.
• Continued use of our Climate Action Strategy Dashboard, a public interactive tool that visualises our data, making it easy to explore and understand and integration with broader climate reporting.
• Supporting SMEs to take practical climate action through Heart of the City’s Net Zero Accelerator programme, enabling them to understand and measure their carbon footprint and develop a realistic, actional net zero plan aligned to their business. 

• Data collection challenges: Matching supplier names with financial records (company names can change, and the finance system may retain the legacy name), checking unit inconsistencies (e.g. kilograms vs tonnes), and checking data reporting periods for alignment. Future reporting should plan for these challenges and build in sufficient time and resource for data verification. 
• Supplier engagement is key: Building relationships and providing clear guidance helped improve response rates and data quality.

For more information, please contact Lucy Potashnick and Maddie Baker via email at [email protected]