The latest annual report of the IPA to the Treasury and the Cabinet Office has rated the HS2 project red. The rating is explained here. In all previous reports HS2 has been rated amber-red
Successful delivery of the project appears to be unachievable. There are major issues with project definition, schedule, budget, quality and/or benefits delivery, which at this stage do not appear to be manageable or resolvable. The project may need re-scoping and/or its overall viability reassessed.
A link to the report is here: HS2 is mentioned on page 35. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/899401/IPA_AR_MajorProjects2019-20.pdf