The construction boss charged with getting HS2 to Euston says he is "absolutely confident" it can be achieved.
But Huw Edwards warned of the financial dangers of mothballing the tunnelling machines at Old Oak Common as he insisted the mega station in north-west London would not be left as the permanent terminus for the line.
HS2 bosses this week celebrated the completion of a logistics tunnel — used to remove excavated spoil from the "front line" once digging to Euston commences — as a key "pit stop" along the road to completing the southern section of the new line that will link London and Birmingham.
Mr Edwards, who has been handed additional responsibility for the Euston tunnels and HS2 station, was unable to set an opening date for the Euston leg.
But he scotched fears that Old Oak Common — which was only envisaged as an interchange station with the Elizabeth line and GWR services — would become HS2’s southern terminus after the Government ruled out using taxpayers’ cash to take the line to Euston.
Mr Edwards insisted the Government was "absolutely committed to getting to Euston".
He told the Standard: "The Government is committed to tunnelling to Euston, committed to developing out Euston station, and I’m absolutely confident that that will be the end point of the HS2 railway."
He added: "There is no doubting it — the most economic way is to continue tunnelling once you have commenced."
It came as Rishi Sunak came under renewed pressure this week to commit to HS2 reaching Euston.
Responding to Labour MP Rupa Huq, whose constituency includes Old Oak Common, the Prime Minister said: "We are working with the private sector to raise private money, save the taxpayer money and deliver the connection to Euston as planned."
On Tuesday, HS2 celebrated the breakthrough of a tunnel boring machine that had been digging an 875-metre "bypass" tunnel linking Old Oak Common and lines west of the site.
Old Oak Common station is due to open in the next five to nine years. HS2 will almost halve the journey time between Euston and Birmingham to 49 minutes.