Both the Department and HS2 Ltd told us that they were working together to reach an agreed methodology including drawing on third–party technical advice on cost estimation and, to ensure that the underpinning assumptions of future estimates are agreed, establishing an oversight group with HM Treasury representation.18 The Department expressed confidence that there would be agreement on the methodology in the coming two to three months.19

Both the Department and HS2 Ltd told us that they were working together to reach an agreed methodology including drawing on third–party technical advice on cost estimation and, to ensure that the underpinning assumptions of future estimates are agreed, establishing an oversight group with HM Treasury representation.18 The Department expressed confidence that there would be agreement on the methodology in the coming two to three months.19 Type: conclusion | Number: 11 | Response status: accepted Government response: 2.1 The government agrees with the Committee's recommendation. Target implementation date: Spring 2026 2.2 The Secretary of State has commissioned the CEO of HS2 Ltd to undertake a comprehensive review of the programme, including HS2's current cost position and the capability and culture of HS2 Ltd,