HS2 is to be Britain's second purpose-built high-speed line after High Speed 1, which connects London to the Channel Tunnel. The majority of the project is planned to be completed between 2029 and 2033.

The full completion of High Speed 2 (HS2) in the United Kingdom has undergone a significant "programme-wide reset" as of early 2026. The initial phase, Phase 1 (London to Birmingham), is currently deep in construction with a revised opening window between 2029 and 2033. In 2026, major milestones are being met, such as the completion of the Chiltern tunnel ventilation shafts and the landscaping of the Colne Valley viaduct area. However, following the 2023 cancellation of the northern legs (Phase 2a to Crewe and Phase 2b to Manchester), the project is now focused on the high-speed link between Old Oak Common in West London and Curzon Street in Birmingham. The extension from Old Oak Common to London Euston is still slated for much later, potentially the late 2030s, pending final funding settlements and tunneling approvals. For 2026 observers, the project remains the largest infrastructure endeavor in Europe, with over 30,000 workers currently active on sites across the Midlands and the South East.