Patrick McLoughlin: HS2 essential to UK rail network
9 September 2013 Last updated at 08:49 BST
A report by the Public Accounts Committee has made several criticisms of the planned HS2 high-speed rail link.
The report, published on Monday, said the Department for Transport was failing to present a "convincing strategic case".
Chair of the Public Accounts Committee Margaret Hodge told the Today programme: "We need to be convinced of the economic case.
"We need better understanding of the costs... and we need to have better understanding of how the department is going to plan the project so that it is going to be in time."
Transport Secretary Patrick McLoughlin said: "This is planning for the long term future of our railways. It is essential that we have good connections between our main cities."
First broadcast on the Today programme on Monday 9 September.