Transport Secretary Mark Harper has confirmed HS2’s full business case now stands at £102.7 billion, a near doubling of the original £55.7 billion estimate in 2015, as the government vowed to push the project to completion despite rising costs and delays.

Harper admitted during a statement to Parliament on Tuesday that revised projections show trains on the network will operate at speeds 10% slower than initially planned, citing engineering challenges and route adjustments as key factors in the slowdown.

The Department for Transport’s updated business case, published late Monday, reveals the eastern leg of the project between Birmingham and Leeds has been scrapped entirely, while the western leg to Manchester faces significant redesign to cut costs.

Industry experts warn the cost overrun could trigger further scrutiny over value for money, with the National Audit Office already flagging concerns in a 2023 report that highlighted poor risk management and a lack of transparency in earlier projections.

Harper defended the project in his statement, arguing that HS2 remains critical for economic growth and connectivity, despite the ballooning budget. He pointed to contracts already signed with firms like Balfour Beatty and Alstom, which he said would ensure delivery of the remaining phases.

Opposition MPs, including Labour’s Louise Haigh, have already criticised the government’s handling of the project, calling the revised costs “a national embarrassment” and demanding an independent inquiry into the procurement process.

• 📊 The revised business case shows a 38% increase in costs since the last update in 2020
• 🔍 Engineering challenges, including ground conditions and tunnelling, have added £12 billion to the bill
• ⚠️ The scrapping of the eastern leg means Yorkshire will lose direct high-speed links, relying instead on upgrades to existing routes

The government has pledged £4.2 billion in additional contingency funding for 2026, but Harper refused to confirm whether further delays or cost increases could emerge as construction progresses on the remaining sections.

Construction on the London to Birmingham leg is now expected to finish in 2033, while the Birmingham to Manchester segment won’t open until 2036 at the earliest, according to insiders familiar with the timeline.

1. Phase 1 (London to Birmingham) — Now due 2033, delayed from original 2026
2. Phase 2a (Birmingham to Crewe) — Delayed to 2035
3. Phase 2b (Crewe to Manchester) — Scaled back, opening no earlier than 2036

The scrapping of the eastern leg has left Yorkshire without direct high-speed rail, prompting regional leaders to demand a new economic assessment to determine the impact of losing a key infrastructure project.