High speed rail from London might not be achieved in the 2020s because of "endless dither and delay" by the Government, former transport secretary Lord Adonis has warned.
The first leg will go to Birmingham, with another spur planned to go to Manchester.
The Labour peer said plans to get HS2 on to the statute book by the end of this parliament could fall victim to wrangling between the coalition parties ahead of the next general election, scheduled for 2015.
The highly-controversial £33 billion network was given the go ahead in January, with a line between London and Birmingham expected to open by 2026.
Urging Prime Minister David Cameron to get a grip on the issue, Lord Adonis said: "If infrastructure projects are going to happen they need someone who is going to drive them forward, and that simply isn't present.
"We are already on the second transport secretary since the election, the Transport Department has had three permanent secretaries in the last two years. There has been endless dither and delay.
"No one is gripping this, no-one is driving this forward. There should have been a Bill for HS2 in the Queen's Speech when apparently we are instead going to be spending month after month debating House of Lords reform."
Lord Adonis, an architect of the high speed rail plan in the last Labour government, said there were delays to the consultation on compensation for householders affected by the project and in publishing the route north of Birmingham.
He told BBC Radio 4's Today programme: "I think there is now a very good chance that the legislation won't pass in this parliament. It could well get caught up in all the politics leading up to the next election, which I think given the state of the coalition could lead to a very significant further delay and it means that we may not see HS2 now in the 2020s."