MENSA

Military Capability

Record date: 31 March 2026

Whole-life cost: £3.6bn
Published schedule: 31/08/2011 – Exempt under Section 24 - National security
NISTA delivery confidence: AMBER
Senior responsible owner: Tom Bennington

What the project is for

MENSA is the replacement capability for assembly and disassembly of current and future nuclear warheads in support of HMG's strategic deterrent.

Departmental delivery commentary

Compared to financial year 2024/25-Q4, the NISTA/SRO Delivery Confidence Assessment rating at 2025/26-Q4 remained at Amber. This is primarily due to the following factors. 1. Reflects ongoing challenges and a testing supply chain environment, despite positive developments such as improved understanding of the remaining scope and cost to completion, better schedule adherence, and progress towards completing construction prior to commissioning and handover.

Schedule

Exempt under Section 24 - National security

Cost

Compared to financial year 24/25-Q4, the project's departmentally agreed Whole Life Cost at 25/26-Q4 increased from £2929.600 to £2930.500. This is primarily due to the the agreed position presented by AWE at the last Financial Year and the change to a new Financial Year.

Benefits

Compared to financial year 2024/25-Q4, the project's departmental-agreed monetised benefits at 2025/26-Q4 remained at £0m.