Lord Mandelson believes the controversial High Speed 2 (HS2) rail line proposed by the government could turn out to be an "expensive mistake".

Although the former business secretary was part of the group that first came up with the plans a number of years ago, he now thinks the development would be a waste of money.

Writing in the Financial Times, he said the Labour government sanctioned the project based on predicted costs of £30 billion, but these estimated figures were "almost entirely speculative".

The superfast line - which will slash journey times between London, Birmingham, Sheffield, Manchester and Leeds - has come under fire ever since the government published detailed plans of the route earlier this year.

Many MPs fear the initiative is far too expensive and the money would be better spent on upgrading the West and East Coast Main Lines.

Mr Mandelson wrote: "There are no simple options when it comes to transport - but I now fear HS2 could be an expensive mistake."