Restoration and Renewal of Parliament: Costing and governance

Status / emerging findings

• Client Board recommends a seven-year phase 1 capped at £3 billion, but wants to keep both 'full decant' and 'partial decant' options live rather than deciding now — adding £95–160 million in extra cost plus unpriced risks.
• Phase 1 design is incomplete; witnesses (Simmonds, MacMillan) claim confidence in the £3 billion figure despite missing specifications, backed by Grant Thornton and Gardiner & Theobald assurance not yet public.
• Committee pressed whether this dual-track approach is prudent or a failure to make a hard decision before spending begins.
• Outcome level 4 chosen in 2023 on a 2.26% cost margin over level 3; detailed comparison of all six options was not made available to the Committee despite claims of earlier discussion.

Why it matters

Parliament will spend billions on this project over the next decade; if governance and costing are weak now, cost overruns and delays will be inevitable and politically toxic.

Tone arc

Opened procedural (examining costing method and assurance), sharpened into scepticism after the March 2026 evidence session when Committee realised parallel options would cost extra and full specification was absent.

Key witnesses

Charlotte Simmonds (Client Team Managing Director), Russ MacMillan (Restoration and Renewal Delivery Authority CEO), Grant Thornton (external assurance), Gardiner & Theobald (external assurance)