The EU must end "persistent delays" over the UK's access to the bloc's scientific research programmes after Brexit, the government has demanded as it launched legal action.
It said the delays have prevented the UK from accessing Horizon Europe, the EU's key funding programme for research and innovation, and Copernicus, the earth observation programme that provides data on climate change.
Other schemes that have been affected include nuclear research programme Euratom, and access to space surveillance and tracking.
Foreign Secretary Liz Truss, also the Tory leadership frontrunner, said the EU "is in clear breach of our agreement, repeatedly seeking to politicise vital scientific co-operation by refusing to finalise access to these important programmes".
She added: "We cannot allow this to continue. That is why the UK has now launched formal consultations and will do everything necessary to protect the scientific community."
Ministers have written to the European Commission to launch dispute resolution proceedings after the UK negotiated access to a range of EU science and innovation programmes as part of its post-Brexit trade deal with the EU in 2020.
But the Foreign, Commonwealth and Development Office (FCDO) said it has now been more than 18 months and the EU has "still refused to finalise UK access" which it said is "causing serious damage to research and development in both the UK and EU member states".
Labour accused the Tories of "starting rows with the EU to appeal to their Tory base" as Ms Truss faces Rishi Sunak to replace Boris Johnson.
Ms Truss said: "The EU is in clear breach of our agreement, repeatedly seeking to politicise vital scientific cooperation by refusing to finalise access to these important programmes. We cannot allow this to continue.
"That is why the UK has now launched formal consultations and will do everything necessary to protect the scientific community."
Earlier this month, a cross-party group of peers on the House of Lords' Science and Technology Committee concluded in a report that the government's international science policy "has been somewhat incoherent".
It warned: "Association with Horizon Europe has not been secured, which risks harming the UK's reputation further and jeopardising the quality of its science base."
European Commission spokesman Daniel Ferrie said: "The commission takes note of the UK's request for consultation and will follow up on this in line with the applicable rules, as set out in the Trade and Cooperation Agreement."
Labour's shadow foreign secretary, David Lammy, said: "Both the EU and the UK need to show more flexibility, but the Conservatives' reckless and law-breaking approach to the protocol is helping to prevent Britain gaining membership of Europe's £80bn Horizon scheme that funds vital scientific innovation and research.
"Instead of continuing the pattern of starting rows with the EU to appeal to their Tory base, the next prime minister should sit down with all parties to ease the tensions and find agreement in the national interest."
Earlier this year, the EU launched legal action against the UK for failing to comply with the Northern Ireland Protocol as the government introduces legislation threatening to override the post-Brexit agreement.