UK researchers can participate in larger Horizon projects if UK is a Horizon members. Much more easy to have joint research projects if the budget can be shared

UK researchers can participate in larger Horizon projects if UK is a Horizon members. Much more easy to have joint research projects if the budget can be shared across the project, rather than split up with research outcomes/outputs having to be accounted for across UK/Horizon boundaries. In reality many UK institutions that were part of Horizon projects simply left them or didn't join as partners on applications.