To fit with the government’s scaled-down plans the station at Old Oak Common will have to be completely redesigned with more platforms to act as a terminus rather than a through station as originally planned. And that means more delay, and much greater costs.
Having been whisked on HS2 at 250 mph to Old Oak Common, passengers will be forced to get out and transfer to the new Elizabeth Line to get to central London (or anywhere else!), a line that has been extremely successful and whose trains are already very crowded.
Despite the high speed of the HS2 trains, there is likely to be no journey-time reduction for around two-thirds of passengers. Many passengers may see a through train to Euston on existing lines as more convenient, undermining the benefits of reducing overcrowding on the West Coast line.
• See also Where's the capacity?