As UK-based European stakeholders, we are deeply concerned about the threat that Brexit — particularly a ‘no deal’ scenario — poses to international research (Nature 572, 13–14; 2019).

Uncertainties arising from the 2016 Brexit referendum have already undermined the attraction for foreigners of doing research in Britain. In our view, the various scenarios are all likely to damage research initiatives.

‘Shadow membership’ and ‘third country’ scenarios, for example, represent different degrees of cooperation with the European Union. These could introduce new challenges, and perhaps opportunities, with regard to partnerships, taxes and regulations. But they would still curtail the freedom enjoyed by European academics. The UK government would need to increase its research budget to offset the loss of the EU funding.

Scientific excellence is underpinned by researcher mobility, adequate resources and regulations that foster long-term stability and planning. A no-deal scenario would result in fewer European collaborations, diminished resources and constrained legal frameworks. It would therefore present a grave danger to science.