Britain has launched dispute procedures with the European Union over its exclusion from the bloc's scientific research programmes, using a mechanism set out in a post-Brexit deal.
This is the first such dispute launched by the UK against the EU since Brexit.
The British government said in a statement late Tuesday that it has launched action "set out in the UK-EU Trade and Cooperation Agreement (TCA) to resolve disputes between the UK and EU".
The action was taken over "persistent delays" to its access to EU science programmes, it said.
It added that the UK had negotiated access to these programmes in 2020 but the EU "has still refused to finalise" its inclusion in academic programmes.
It said it remained excluded from the bloc's flagship Horizon Europe programme that funds research, nuclear regulator Euratom and Copernicus satellite monitoring group.
The UK government said it has written to the European Commission to launch dispute resolution proceedings and expects "constructive engagement".
"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," said Foreign Secretary Liz Truss.
The UK said if the EU refuses, it has "prepared an alternative set of programmes to support UK scientists and researchers".
Provision for such formal consultations on disputed topics is part of the UK-EU post-Brexit trade deal -- known as the Trade and Cooperation Agreement (TCA).
The British government controversially left the European Erasmus student exchange scheme after Brexit, launching its own scheme called the Turing programme.
European Commission spokesman Daniel Ferrie told journalists on Tuesday that the EU had not yet received formal notification of the submission of dispute procedures from the UK.
He said the EU would follow up, but there were "serious difficulties" since the post-Brexit trading accord does not oblige the EU to make the UK an associate on such programmes, or give it a precise deadline to do so.