Devolution is weakening the UK's ability to influence the EU's growing hold over health policy, a report from the Nuffield Trust warns.
Political conflicts between ministers representing each of the four UK nations mean devolution has "inexorably reduced its ability to create a single united 'line'", according to report author Scott Greer.
Professor Greer, a senior research fellow at the London School of Economics, said: "There is a real risk that health policy will be made not by health policy makers but by EU lawyers, economics ministers, or other groups that do not understand or sympathise with the specific problems and goals of health policy."
The high number of former NHS managers and health professionals is also weakening the UK's influence over EU health policy, the report says. Department of Health staff in Whitehall are responsible for co-ordinating UK health policy in the EU, but many "lack the networks of traditional civil servants that underpin information-sharing and handling interdepartmental relations".