The HS2 announcement came just days before the government announced a consultation on the potential development of a new airport in the Thames estuary. This demonstrates the typical lack of joined up thinking that has sadly plagued British governments of all colours for far too long.
Whilst few in the aviation industry have any appetite for these proposals (see 10 reasons why it is unlikely to happen), if they are taken seriously, this new airport would need a whole range of new surface access provision, including fast rail links both from central London and to the rest of the country. It is likely that both the Crossrail route and HS1 would be used to serve the airport with a combination of regional and long-distance trains, yet is there provision in the St Pancras complex to cater for an additional airport shuttle of this nature?
This totally changes the way Euston should be redeveloped. Instead of being set up as a terminus, Euston's high-speed platforms would need to be rotated through 90°, and many trains would then run through and terminate at the Thames airport. The current HS1 line has potential for extra capacity, as it is currently only used by 30 Eurostar trains each day to Paris and Brussels and 4 services each hour using the Southeastern Highspeed route.
A new airport of this size would also create a considerable displacement in London's geography, with so many businesses located in the M4 corridor. Whilst some may relocate to the up-and-coming Thames Gateway region, others would be more likely to stay put, in which case a fast, direct service to the airport from locations such as Oxford, Reading, Maidenhead and Slough would be needed, using trains similar to the ones currently operating on HS1, and without taking the much slower Crossrail route through central London. Consideration would need to be given to providing a connection between the Great Western route and HS1 via Old Oak Common. This could be a costly change to make later, whereas Euston could not be remodelled again after going through such major changes.
The government needs to decide very quickly – either accept, as most in the industry already do – that the Thames Hub is a dead duck, or get busy turning those plans for Euston from portrait into landscape.