Highlights
- Original plan for 360km/h speeds created bespoke design that inflated costs beyond control.
- First trains between London and Birmingham now expected from 2035, not 2033.
- Project cost has soared from £32.7 bn in 2011 to potential £100 bn for reduced route.
Stephen Lovegrove, former national security adviser, told The Times that trying to build one of the world's fastest railways was a major mistake that caused HS2's problems from the start.
The decision to design tracks for speeds of 360km/h forced engineers to create highly specialised infrastructure that made costs spiral out of control.
Original design flaws
The review shows how officials chose to start building on the hardest section between London and the West Midlands, making early problems worse.
Transport secretary Heidi Alexander is expected to confirm speed limits will drop to 320km/h to cut costs.
Lovegrove found that politicians put constant pressure on civil servants and HS2 Ltd to keep the project moving, even as costs kept rising.
People interviewed told The Times that ministers were so worried about the project being cancelled that they let spending get out of control.
"There is little doubt that all players felt under significant pressure from ministers to keep things moving," the review states.
The main contract was given out before designs were ready, with poor planning for managing risks. Cost estimates proved "disastrously wrong," according to Lovegrove.
The project has changed completely since 2011, when the £32.7 billion plan promised connections between London, Birmingham, Manchester and Leeds by 2025.
Now only the Birmingham section will use new tracks, with HS2 trains continuing on existing West Coast Main Line infrastructure.
Current estimates suggest costs could reach £100 billion, equivalent to £1 billion per mile. First services between London and Birmingham are expected no earlier than 2035.
Previous Conservative governments lost control of the project, according to government sources. HS2 is now led by Mark Wild and Mike Brown, who previously rescued the troubled Crossrail project.
