§ Lord Kennetasked Her Majesty's Government:
What has been the cost per metre of other "long" tunnels the Highways Agency has undertaken, and in each case what were the reasons for choosing a tunnel.
§ Viscount GoschenThe cost per metre of tunnels undertaken by the Highways Agency which are under construction or have been opened within the last 10 years and for which figures are available are shown in the table. The costs have not been adjusted for inflation, changes to the rate of Value Added Tax or any outstanding construction claims.
Any simple comparison, based on unit costs per metre alone, could be very misleading, given the many differing factors which will have applied in each case, for example whether the tunnel is located in an urban or rural area; local geological and groundwater conditions, total carriageway width and the tunnel construction method used.
The reason a tunnel was chosen in each particular case would have been dependent on a careful and balanced consideration of such issues as economic and environmental benefit, traffic volumes, and the engineering practicalities for the particular circumstances that prevailed.
Location Length (metres) Cost (£m) Cost (£ per metre) Hatfield Tunnel (opened 1986) (A1(M), Hertfordshire) 1150 23.60 20,522 Saltash Tunnel (opened 1988) (Saltash, Cornwall) 400 8.5 21,250 Round Hill Tunnel (opened 1993)(A20, Kent) 390 13.20 33,846 Green Man Tunnel1 (Hackney-M11, London) 174 7.04 40,460 George Green Tunnel1(Hackney-M11, London) 300 8.43 28,100 Southwick Hill Tunnel1 (A27, Brighton) 490 14.9 30,408 Fore Street Tunnel1 (A406, London) 310 17.0 54.839 Meir Tunnel1 (A50, Staffordshire) 284 6.01 21,162 1 Tunnel under construction