Ministers have welcomed the decision by the world's biggest fast food chain McDonald's to take "supersize" portions off its menus.

The burger giant said the move was designed for business reasons but acknowledged the growing prominence of thh obesity epidemic in public debate.

Health secretary John Reid said the decision was a perfect example of the partnership approach the government favours.

“We are prepared to use legislation but we know that we cannot make the nation healthy by diktat," he said.

"The government can’t solve this problem on our own. I hope this is the first of many steps taken by every organisation that can make a difference."