Beyond the High speed Network? After Phase 1 that will everywhere that isn't Brum or London. Even when complete it will leave Bristol, all of Wales, Scotland and East Anglia, which is a far chunk of the UK.
I was referring to both phases of HS2, not that it makes much difference - even major cities like Birmingham, Manchester and Leeds would struggle to fill a daily service to Paris based on those currently going by air.
A Liverpool Paris service would take about as long as the flight, once you take into account checkin times. Extending Liverpool London paths to Paris via OOC would take care of most of the Path issues.
Unless there's a relaxation of border and security controls you can't simply extend a domestic service through the channel from either side as all passengers have to go through check-in - this is the problem facing any new international service.
The Germans seem keen happy to plan a 5 hour route to London Liverpool Paris would be less
A plan for which there are precious few details - it is likely to require London-bound passengers to leave the train at Brussels to go through border and security checks, as those on Eurostar services from the south of France currently do at Lille.
It should also be noted that the proposed service between London and Amsterdam/Cologne/Frankfurt is just three trains a day despite these being some of the busiest air-routes in Europe.
As the French managed to modify an ATV then return return it to service, I doubt the modifications are to great.
ATV? If your referring to the tilt prototype, only the unpowered trailers tilted.
What you want is a 225mph+ design with distributed traction to both tilt
and fit the UK loading gauge. Not that used by the Eurostar, but an even more restrictive tilt-profile like those used by Voyagers and Pendolinos.
Even if that was practical, you have to consider the development risks and costs involved, and the inevitable downsides - a heavier and therefore slower design of train causing greater track wear than one without tilt. The extra complexity will also increase maintenance costs and reduce reliability, while the tilt-profile will also compromise the interior space - it doesn't make sense.
The ATP design was for 155mph on runs to Scotland that would make a difference, and as ETCS 2 is already in the works would not require re signalling. What is needed is very good brakes.
The railway network is a lot busier these days and will only become more so - there simply aren't the paths for trains doing 155mph, they'd just catch up conventional services - 'better brakes' is also easier said than done, those used on the ATP were not widely adopted.
Chris