David Miliband has been appointed secretary of state for Environment, Food and Rural Affairs. He replaces Margaret Beckett, who has been appointed foreign secretary in Tony Blair's Cabinet reshuffle.

Commenting on his new portfolio, the new Defra minister said: “I am very excited to be leading a department whose agenda touches everyone's life - from the local environment, to the farm gate, to the future of the planet.

“It is particularly humbling to take on the challenge of climate change, the greatest of global threats. I know there will be those quick to judge over the next few days but I hope my record of delivery over the longer term will speak for itself.”

Miliband entered the Cabinet as minister of communities and local government in May 2005, supporting the deputy prime minister on housing, planning, regeneration and local government.

Details of Defra's new ministerial team have also been announced:

• Minister of state: Ian Pearson MP

• Parliamentary under-secretary (Commons): Ben Bradshaw, MP

• Parliamentary under-secretary (Commons): Barry Gardiner MP

• Parliamentary under-secretary (Lords): Baroness Ashton of Upholland