THE Government considered tunnelling the entire width of the Chilterns to reduce the impact of High Speed 2, the Transport Secretary Justine Greening has said.

Mrs Greening announced yesterday that some tunnelling will be introduced to lessen the harm to the countryside.

But after looking at the option to bury the whole route through the area of outstanding natural beauty it was deemed unaffordable, at an estimated cost of £1.2bn.

To the surprise of MPs she revealed the tunnels that are proposed will reduce costs by £250 million to £300 compared with not building them at all.

Mrs Greening was addressing The House of Commons in formally announcing the Government has given HS2 the green light.

See related articles for more details on the plans.

It was Wycombe MP Steve Baker, an opponent of the scheme, who unveiled the information when he asked: “Will the Secretary of State consider tunnelling the entire width of the Chilterns?”

Mrs Greening replied: “Yes, I did that. That approach would have cost £1.2 billion and I believe it is unaffordable.”

Labour MP Kevin Brennan later raised further questions on the tunnelling.

He said: “Did she say that the Chilterns tunnel would cost £250 million to £300 million less than the cost would be without it?

“That raises the question why, if it is cheaper to tunnel, she is not burying the entire line. Will she please give us the true figure for building the tunnel?”

Mrs Greening said: “It will cost £250 million to £300 million less. The hon. Gentleman asked why we cannot tunnel the whole way under the Chilterns. Of course that is predominantly an engineering question concerning the amounts of spoil and the geographical nature of the land that we are going through.

“It is quite a complex question but the brief answer is yes, it really is more cost-effective.”

Shadow Transport Secretary Maria Eagle said of the mitigation measures for the Chilterns: “None of these measures addresses the impact on the Chilterns as effectively as would a route via Heathrow.”

Labour proposed an alternative route recently.

Alluding to Amersham and Chesham MP Cheryl Gillan, the Welsh Secretary, Mrs Eagle said: “It is the Government’s own stubbornness that has forced them to commit themselves to significant additional spending to prevent a Cabinet resignation.”

Mrs Eagle added: “What assessment of value for money has she made in respect of the costs of these measures, compared with those of offering greater protection to the Chilterns through a different alignment?”

Mrs Greening said: “I want to emphasise that I looked very hard along the entire line. I understood the specific concerns people had in respect of this AONB, and I took them very seriously, but I looked at the whole line to see how we could mitigate its impact on local communities wherever possible, because that is important and the right thing to do.

“The changes in the Chilterns that we have made will result in that stretch of the line costing in the region of £250 million to £300 million less, because the engineering solutions we have found will involve less use of deep cutting.

“That will mean that we have less spoil, and the removal of spoil is often what causes huge expense.”