Tony Blair has been lobbying for George Bush's support for a new international treaty on global warming, reports the Times.

Downing Street has confirmed that the prime minister had held "lengthy discussions" with the American president about a new initiative.

The deal would involve scientific agreement on the scale of the threat and an international programme to develop the technology needed for renewable energy.

The prime minister held talks in Downing Street last week with John McCain, the influential Republican senator, over how to broker an agreement.

Ministers have admitted that they are set to miss targets set out in successive Labour manifestos for cutting greenhouse gas emissions by 20 per cent.

Meanwhile, the Department for Environment, Food and Rural Affairs has published its five-year plan.

The strategy promises farmers a radically simplified system of subsidies which will eradicate bureaucracy and allow them to respond to what their customers want.