On 8 April 2021 and 13 December 2021 we consulted on proposed amendments to the conditions that attach to the project licence of Bazalgette Tunnel Limited (Tideway). Initially, the amendments were solely to deal with the impact of Covid-19 on Tideway but, subsequently, we agreed to also amend the way a financing mechanism in the project licence works (the Financing Cost Adjustment Mechanism (FCAM)). These licence amendments were made on 16 March 2022. In both these above consultations we included information on a proposed change to the Planned System Acceptance Date but said that a change to that date would be made subsequent to the above two changes. We have now modified Tideway's licence (October 2022) to change the Planned System Acceptance Date from 28 February 2027 to 31st August 2027 and the purpose of this document is to set out our reasons for doing so. The Planned System Acceptance Date is the date at which the operation of the Thames Tideway Tunnel is handed over to Thames Water Utilities Limited (Thames Water).