This practical guidance relates to the Procurement Act 2023 regime As of 24 February 2025, the main provisions of the Procurement Act 2023 (PA 2023) are in force. Procurements begun on or after this date must be carried out under PA 2023 (where applicable), whereas those begun under the previous legislation (the Public Contracts Regulations 2015 (PCR 2015), SI 2015/102, the Utilities Contracts Regulations 2016 (UCR 2016), SI 2016/274, the Concession Contracts Regulations 2016 (CCR 2016), SI 2016/273, and the Defence and Security Public Contracts Regulations 2011 (DSPCR 2011), SI 2011/1848) must continue to be procured and managed under that legislation. This practical guidance compares the key features of public procurement under PA 2023 and PCR 2015, SI 2015/102. For background reading on PA 2023, see Practice Note: Introduction to the Procurement Act 2023—PA 2023 and Does the Procurement Act 2023 apply?—flowchart. For background reading on PCR 2015, SI 2015/102, see Practice Note: Introduction to public contracts procurement—pre PA 2023 [Archived] and Public procurement procedure selection—pre-PA 2023—flowchart