THE Government faced calls to review its commitment to a new high-speed rail line after "unrealistic estimates" of demand for the existing link between London and the Channel Tunnel in Kent cost taxpayers nearly £5 billion, MPs have found.

A report by the Commons Public Accounts Committee found the 68-mile HS1 line has so far cost £4.8bn in subsidies, largely as a result of planners not properly taking account of the boom in budget air travel or competition from ferries.

HS2 will see high-speed rail link London, Birmingham and further north, though no decision has yet been made to extend it to Scotland.