A source said a Network Rail review of the two main alternatives favoured by opponents concluded they could not "generate the capacity" needed.
The government is due to make its final decision on the £17bn HS2 scheme during the coming week.
The news comes at a time when the new “Fyra” high-speed service in the Netherlands — opened just two years ago — is close to financial collapse with passengers shunning its premium fares and trains running up to 85 per cent empty. The line, between Amsterdam, Rotterdam and Breda, cost taxpayers more than £7 billion to build but is losing £320,000 a day amid disastrous levels of patronage.
A Dutch passenger pressure group, Voor Beter OV (For Better Public Transport), is now taking the national rail operator to the Netherlands’ competition tribunal after it slowed down services on the regular network in an apparent attempt to drive passengers on to the high-speed line.