Dame Anna Dominiczak, Regius Professor of Medicine at Glasgow University, said any changes which would lead to Scottish or UK patients being excluded from clinical trials would be “almost criminal”.
She said Scotland is famed for excellence in clinical trials, and an agreement to remain in the European network for these once the UK leaves the EU should be part of the Brexit deal.
Giving evidence to Holyrood’s Health and Sport Committee, she said: “It is absolutely essential because otherwise NHS patients, research, everybody is losing out.
“I cannot even imagine how trials that are ongoing, new trials that need to be done, how UK patients, Scottish patients would be excluded. This is almost a criminal offence.”
She warned against any differences in medical frameworks, saying it would not be easy to replace the existing networks with a global version.
She said: “It is very important to speak up that we do need to belong to European regulations for drugs, devices and clinical trials.
“If we try to be a little different we will pay for it very dearly in many levels of patient benefit.”
Dame Anna also urged MSPs and MPs to ensure scientific funding remains at least at its current level following Brexit to help prevent researchers being targeted by overseas institutions, mentioning those in Australia, Ireland and Germany.
“Any messaging that things get weaker... would be really lethal at this stage for us,” she said.
“Other countries, this is for them an opportunity to poach people.”
She added since the Brexit referendum there are already less applications for EU research funding being submitted and leading to less money for Scotland and the UK.