Relaxing regulations on the collection and use of patient data will help the UK to become the “best place in the world to conduct cutting edge research,” prime minister David Cameron said in a speech at the launch of the Global Health Policy Summit in London.

He told a meeting of around 500 policy makers, politicians, scientists, and business leaders from around the world on 1 August that he had come to “sell what was great about Great Britain.”

He said that changes would be made to the NHS Constitution so that patients would have to opt out if they did not want their data to be collected and used for research …