David Cameron has defended the government's plans for spreading wind farms across the country despite criticism from his own backbenchers.

The prime minister insisted he had sympathy with concerns, but there were "perfectly hard-headed reasons" for encouraging the sites.

The comments came in a letter responding to more than 100 Tory MPs who had called for the scrapping of subsidies for "inefficient" on-shore wind power.

They also complained that planning policies were putting national energy policies ahead of local objections.

In the missive - addressed to the organiser of the original letter, Conservative MP Chris Heaton-Harris - Mr Cameron denied that the issue went beyond targets for renewable energy and greenhouse gas emissions.

"On-shore wind plays a role in a balanced UK electricity mix, alongside gas, nuclear, cleaner coal and other forms of renewable energy," he wrote. "A portfolio of different supplies enhances energy security and prevents the UK from becoming over-reliant on gas imports."

Mr Cameron added: "I am also determined that we seize the economic opportunities in renewable energy supply chains as the global race for capital in low-carbon sectors intensifies."

The PM stressed that the Government was already proposing to cut subsidies to on-shore wind by 10% to reflect a fall in building costs.

Mr Heaton-Harris told the Guardian: "I obviously didn't expect the Prime Minister to just say: 'OK, you are right,' and change policy in this area and I am pleased he understands the massive concern that local residents have about these plans.

"However, those who signed the letter would like to see a cut in subsidy to on-shore wind greater than the 10% proposed, and hope that our suggested amendments to the national planning policy framework are taken on board.

"We are also concerned at how the cost of this type of renewable energy is adding to fuel poverty."