Palace of Westminster refurb cost surge: phasing and risk notes for project teams
Reviewed by Tom Sullivan
First reported on The Construction Index
30 Second Briefing
Cost estimates for restoring the Palace of Westminster have risen to £18.7bn, nearly triple the £5.7bn upper figure set a decade ago, with current maintenance already running at £1.5m per week. The R&R Client Board proposes a £3bn, seven‑year first phase starting this year, including temporary debating chambers, new office space, underground works, a river delivery jetty and preparation for restoring Cloister Court and refurbishing Victoria Tower. MPs must now choose between a full decant taking 19–24 years at up to £11.5bn, or an EMI+ in‑occupation scheme lasting up to 45 years at £18.7bn, with each year’s delay adding £70m plus £250m–£350m in inflation.
Technical Brief
- Phase one capex is explicitly capped at £3bn over seven years of enabling works.
- Temporary debating chambers and office accommodation must be constructed and commissioned before any whole‑building decant.
- Early underground construction includes new sub‑surface routes and services, implying complex works beneath a live heritage structure.
- A new river delivery jetty is planned to handle construction logistics and reduce road haulage.
- Medieval Cloister Court restoration requires preparatory works in phase one, suggesting staged conservation and structural stabilisation.
- Interior refurbishment of Victoria Tower is bundled into the initial phase, front‑loading high‑risk heritage fabric interventions.
- The current hydro‑pneumatic sewage ejector system, by Isaac Shone, indicates ageing critical M&E infrastructure needing full replacement strategy.
- Previous partial decant sequencing (Lords then Commons) has been abandoned, simplifying phasing but concentrating programme risk into two binary options.
Our Take
The Palace of Westminster scheme now sits at the very top end of UK public-building refurbishments in our infrastructure database, with the £18.7bn EMI+ ceiling eclipsing even major rail and nuclear upgrade envelopes on a like-for-like capex basis.
The current £1.5m-per-week maintenance burden and £70m-per-year delay cost effectively create a hard financial backstop; in comparable UK heritage assets, such thresholds have typically triggered a shift from piecemeal works to a single-programme delivery model once annual holding costs exceed a few per cent of projected capex.
The contrast between the shorter but more capital-intensive full decant option and the 45‑year EMI+ path mirrors trade-offs seen in other long-running UK civic refurbishments, where extended on-site occupation tends to reduce annual budget pressure but materially increases lifecycle risk exposure to changing codes, political cycles and construction inflation.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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