Originally Posted by
stut
And wouldn't an HS2-HS1 link be far more easily achieved by linking Euston with St Pancras, a few hundred yards away?
Half a mile. IIRC the plan was however to bore an additional tunnel (or even two?) from Old Oak Common to Chalk farm (the tunnels to Euston extend to the Western end of Delancey St) at wich point the link would use the existing North London line to connect to HS1.
I'm not sure if the link would've made things easier. It would have made immigration and security controls so much more complex.