PRIME Minister and Witney MP David Cameron's father-in-law has renewed his attack on the Government's HS2 high-speed rail project.

Viscount Astor, Samantha Cameron's stepfather, who lives at Ginge Manor, near Wantage, is a staunch opponent of the plan for a London-Birmingham link, which would cut across north-east Oxfordshire between Finmere and Mixbury.

Last night he used a debate in the House of Lords to attack the business case for the new line.

He said the Government's claims for the £33bn line, which would eventually run on to Manchester and Leeds, rested on Department of Transport figures of rising railway use.

But the department's record in projecting future passenger numbers was "not good", he said, warning the number of users on HS1, the line from London to the Channel Tunnel, had initially been overestimated three-fold.

He told peers: "The projected benefits are largely dependent on business use and business use is changing. Why travel so often when Skype and internet conferencing is becoming the norm?

"Reductions to already short journey times are largely irrelevant to business efficiency as carriages are now linked to the internet and provide a good working environment."

Viscount Astor, who also complained about the damage that would be done to the Chiltern hills, called instead for an upgrade of the existing lines which could be achieved "at a fraction of the cost".

For the Government, Earl Attlee said major infrastructure projects were generally controversial: "The Jubilee line extension at the time of its conception was controversial, but where would we be without it now?"

He said the country could not just "make do and mend" and added that without HS2 "our main north to south rail arteries will become increasingly disrupted and overcrowded, damaging both our economy and our way of life".

Viscount Astor first attacked the HS2 scheme in an article in the Spectator magazine, published in January.