The health service should consider giving people NHS-branded bicycles to help them get fit and contribute to tackling climate change, according to an organiser of a landmark conference on sustainability and the NHS.

Hugh Montgomery, director of University College London's Institute of Human Health and Performance, said he wants the NHS to copy the success of the "bag-for-life" campaigners who galvanised the fight against plastic bags.

"An NHS brand bike is a great idea. It's cheaper and healthier in the long run than putting someone on cholesterol-lowering drugs," Professor Montgomery said. "I am sure that with economies of scale and the right business partners, we could make an NHS mountain bike for around£50."

The conference, billed as a call to arms to the NHS to lead the fight against global warming and the toll it would take on mortality and illness, was attended by public health doctors, physicians and policy makers.

Ian Roberts from the London School of Hygiene and Tropical Medicine said: "Six per cent of UK road trips are on NHS business and that comes out of the taxpayers' pockets - we could reduce a lot of face-to-face meetings and use more teleconferencing."

Sir David King, the government's former chief scientific officer, who has said that climate change is a greater problem than terrorism, told the conference that technological solutions were available now or within reach. But without immediate action at local and global level, climate change would be irreversible.

"By 2050 we could see average summer temperatures as high as 2003, which led to 35,000 excess deaths in Europe."

David Pencheon, leader of the new NHS Sustainable Development Unit, which will work with the 10 strategic health authorities to improve the energy efficiency and sustainability of the NHS, said that with a£17bn purchasing purse and 1.3 million employees, the NHS must take the lead on all fronts, perhaps investing in local sustainable energy generation.

"We want to see the NHS in the vanguard here, demonstrating that we can be environmentally sound. We want trusts not only to switch to low-energy light bulbs but be ahead of the game, switch to next generation LED bulbs. We want trusts to go out and act as patrons of local low-energy schemes," he said.

Dr Pencheon said he would like the regulatory framework to take account of sustainability.