The Housing and Regeneration Policy and Scrutiny Committee of Westminster Council met on 20 November 2025. Councillor Hamza Taouzzale, Chair of the Committee, was scheduled to preside over the meeting. The main item for discussion was the call-in of a cabinet decision regarding the future of the Pimlico District Heating Undertaking.

Call-in of Cabinet Decision: Future of Pimlico District Heating Undertaking (PDHU)

The committee was scheduled to review a Cabinet Decision concerning the 'Future of Pimlico District Heating Undertaking (PDHU) - Outcome of Initial Outline Business Case Analysis', after it was called in by Councillor Paul Fisher, Councillor David Harvey and Councillor Ralu Oteh-Osoka. The original decision report was approved by the cabinet on 16 October 2025.

The call-in was triggered because the three councillors believed that the cabinet had made a decision without sufficient information. Their concerns included:

• Insufficient detail on electrical infrastructure costs.
• Unclear optimisation biases used for each assumption.
• Uncertainty about whether estate re-wiring would be required.
• Concerns about the qualitative critical success factors used in the evaluation.
• Lack of consideration for local air quality impacts from constructing a heat tunnel to Pimlico.
• Unclear reasons for discounting ambient loop Ground Source Heat Pump (GSHP) technology.
• Failure to consider half-hourly electricity tariffs or tariffs with free energy days.
• Lack of financial models for scrutiny.
• Whether flat-level Air Source Heat Pumps (ASHPs) should be reconsidered.
• Lack of analysis of what residents can afford to pay for a heating system.

In response to these concerns, a report was prepared for the committee's consideration. The report included detailed breakdowns of electrical infrastructure costs, explanations of the optimism biases used, and clarifications regarding estate re-wiring requirements. It also defended the qualitative critical success factors used, stating that they adhere to the HM Treasury Green Book framework¹ and consider long-term deliverability, operational performance, resilience, and regulatory risk.

The report also addressed the concerns about the ambient loop GSHP, stating that while technically feasible, it scored poorly against the project's Critical Success Factors due to high capital costs, planning and regulatory interfaces, and delivery risks.

Regarding electricity tariffs, the report clarified that the project's cost and energy modelling follows HM Treasury's Green Book guidance and the Department for Energy Security and Net Zero (DESNZ) framework, using standardised long-term energy price projections rather than short-term or promotional tariffs.

The report clarified that detailed financial models did not yet exist at this stage, but would be developed as part of the next stage of the Outline Business Case (OBC).

In response to the question about Air Source Heat Pumps (ASHPs), the report stated that individual ASHPs were considered but discounted due to access, noise, and aesthetic considerations, as well as the need for extensive electrical upgrades.

Finally, the report addressed the affordability concerns, stating that affordability is a key factor in the project's evaluation and is being assessed in line with HM Treasury's Green Book guidance.

The committee had the option to either note the decision made by the cabinet or refer the matter back to the cabinet with specific matters for reconsideration.

Other Business

The committee was also scheduled to note any changes to the membership, receive declarations of interest from members and officers, and review the minutes of the previous meeting.