The UK is to return to the European Union's £85 billion Horizon science research programme following months of negotiations.
The Government said a "bespoke" new agreement has been signed off with the EU, with UK researchers able to apply for grants and take part in Horizon projects.
Britain continued to participate under the post-Brexit trade deal brokered with Brussels but was frozen out in a tit-for-tat retaliation in a dispute over Northern Ireland arrangements.
The move was immediately welcomed by scientists, after years of warnings that UK researchers have been missing out on collaboration with colleagues in the EU.
Horizon is a collaboration involving Europe's leading research institutes and technology companies. EU member states contribute funds, which are then allocated to individuals or organisations on merit to explore subjects such as medical advances, climate change, and artificial intelligence.
It had been hoped that a British return to Horizon would follow in the wake of the Windsor Framework deal, agreed in February and designed to address concerns over post-Brexit arrangements in Northern Ireland. The breakthrough comes after months of talks between London and Brussels.
Deal Widely Welcomed Across the Health Research Community
Professor Paul Stewart, Academy of Medical Sciences vice president of clinical, said: "Health research is an international endeavour, it relies on supporting the best ideas, but also on creating cross-border networks which is good news for the UK, Europe and the rest of the world. Association sends a very strong message that the UK is open for business and remains a prime destination to work on health research and innovation to improve lives."
Nicola Perrin, chief executive of the Association of Medical Research Charities (AMRC), said: "Finally the news we've been wating for – the UK is rejoining Horizon Europe. Ongoing Government commitment to cross-border collaboration in research is crucial to deliver benefits to patients. This will help improve confidence and stability in UK research, in which charities play a vital role.
"The announcement will be a huge relief to charities, and the researchers they fund."
Michelle Mitchell, chief executive of Cancer Research UK, said: "Horizon Europe association is overwhelmingly in the best interests of cancer patients and scientists, and it is great news for cancer research that agreement has finally been reached between the UK and EU.
Dr Beth Thompson, chief strategy officer at Wellcome, said: "Being able to easily collaborate across borders stacks the odds in favour of scientists looking for solutions to the world's urgent health challenges."
Prime Minister Rishi Sunak said: "We have worked with our EU partners to make sure that this is right deal for the UK, unlocking unparalleled research opportunities, and also the right deal for British taxpayers."