This Practice Note provides an overview of construction and engineering projects in the UK defence sector. It outlines the Ministry of Defence (MOD)’s spending and procurement policies, applicable public procurement rules, the Defence Reform Act 2014 (DRA 2014) and Single Source Contract Regulations 2014 (SSCR 2014), and the use of standard form construction contracts. The core principles of the DRA 2014 and SSCR 2014 are central to MOD procurement, but the landscape is evolving. The Procurement Act 2023 (PA 2023), updated NEC4 frameworks, and strengthened sustainability and SME targets reflect a continued emphasis on transparency, value for money, and innovation across the defence estate. A major restructuring of UK defence began in 2025 with the Strategic Defence Review and Defence Reform programme. This Practice Note reflects policy and legislative changes as of October 2025, including developments under the PA 2023, the MOD SME Action Plan 2022–2025, and updates to the NEC4 contracts (2023 edition). Spending policy Defence is organised into six ‘Top Level Budgets’ (TLBs): • Head Office and Corporate Services