Carriages for controversial high-speed line focus on passenger comfort, innovations and headroom, mock-ups reveal

For now, it remains unclear quite how far any passenger will travel on future HS2 services – whether reaching Euston or on high-speed tracks all the way to Crewe. But however short the journey, an exclusive peek at HS2’s embryonic carriages reveals travellers will be enthroned in “the best seats of any UK trains” – even, arguably, in the toilets.

Conscious of discontent with the “ironing board” seats in some of the newest trains introduced to Britain’s railways, HS2 are putting passengers’ backs and bottoms centre stage.