£17Bn is staggering - and the £5Bn for road improvements even more.
See costs here for roads:
http://www.bbc.co.uk/news/magazine-13924687
£694m for the Glasgow M74 extension: £86.5k per metre.
£155k per metre for the A3 tunnel and..... wait for it........
£250k per metre in today's money for London Dockland's Limehouse Link!