HS2 Birmingham and Fazeley viaduct
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HS2 case uses 'fragile numbers' and outdated research

9 September 2013 Last updated at 19:03 BST

A group of MPs has said the government's case for the planned high-speed rail link is based on 'fragile numbers' and research that is out of date.

The estimated benefits of HS2 are dwindling as costs rise.

Richard Westcott reports.