The government is launching a review of the planned high-speed HS2 rail link - with a “go or no-go" decision to be made by the end of the year, Transport Secretary Grant Shapps has said.
A branch of the rail link is set to run through South Yorkshire and on to Leeds while another stretch of the route is planned to run into North Yorkshire.
The review will consider whether and how the project to connect London and northern England should proceed, looking at costs and benefits.
Mr Shapps refused to rule out scrapping the project entirely and said it was "responsible" to see if it was "going to stack up".
The first segment of the HS2 development between London and Birmingham is due to open at the end of 2026, with the second phase to Leeds and Manchester scheduled for completion by 2032-33.
When asked about the £7bn already spent on the project, Mr Shapps said: "Just because you've spent a lot of money on something does not mean you should plough more and more money into it."
A final report will be sent to the government in the autumn.