The Government should scrap plans to make its proposed high-speed rail (HSR) line the fastest in the world so the countryside can be protected, a green group has said.

Running trains at 250mph on the planned London to Birmingham line could ruin the “beauty and tranquility” of the countryside, according to the Campaign to Protect Rural England (CPRE).

The charity said such excessive speeds required much straighter routes, which made it harder for new tracks to follow valleys, rail lines or motorways.

This meant that only routes that largely cut through open countryside were being considered for the new line.

The CPRE was putting its views to an HSR conference in London today at which Transport Secretary Philip Hammond was due to speak.

CPRE senior transport campaigner Ralph Smyth said: “The plans currently on the table would give the UK the fastest rail line in the world but at huge cost to the tranquillity and beauty of the countryside.

“It’s as if ministers have gone out to buy a family car and come back with a Ferrari. It may impress the neighbours but it’s just not practical.

“The controversy these proposals are generating could derail the Government’s welcome vision to make rail the long-distance travel mode of choice.”

The CPRE said it believed there was a good case for increasing rail capacity, which could include carefully-planned HSR.

The charity is asking for the public consultation on HSR proposed for 2011 to include real choices, including a 186mph route, like the HS1 Channel Tunnel rail link, that runs along existing motorways and railways, keeping intrusion into the countryside to a minimum.

Mr Smyth added: “The Government’s own research shows that travelling at 220mph as opposed to 186mph would only save 3.5 minutes from London to Birmingham.

“We are pleased that the need for more capacity is the driving consideration behind HS2. This should mean that the public should be allowed to have a say on the type of HSR, not just its route.”