The Government announced on Thursday that UK researchers could apply for grants to take part in the collaboration programme after Rishi Sunak secured what he called “the right deal for British taxpayers”.
According to the EU’s estimate, Britain will contribute around £2.2billion (almost 2.6 billion euros) per year to participate in both Horizon and the Copernicus space programme from January 1, when its association membership with the projects begins.
But it will not take part in the bloc’s nuclear technology scheme Euratom.
Professor Bart De Strooper, a dementia researcher at University College London, said there was “little reason for celebration for something that should have happened years ago”.
He told the Observer: “For the past few years we have faced complete uncertainty about what is happening in key research areas. Britain used to dominate the Horizon programme, and it will take a long time to get back to such a position.”
Fellow researcher Professor Sir John Hardy told the paper the UK was a “less attractive” place to do science because of our three-year-absence from the programme and scientists had left the UK after Brexit.
He said: “We have not been part of the great science that Horizon funds and we have lost the trust of European colleagues. Will we leave Horizon again in future, they might ask.”
The Government said the deal includes a “clawback” mechanism, which will see the UK compensated if British scientists receive significantly less money than the UK puts into the programme.
The Prime Minister said talks ended in a “specific deal for the UK that works in the best interest of our researchers and scientists but also in the best interest of British taxpayers”.
Labour called the deal a “relief” but said it comes “too late” for many researchers.
Party leader Sir Keir Starmer said: “I think there is a sense that we have lost two years, that this should have happened two years ago and that is a big loss.”
He said the decision not to join Euratom is a “gap” Labour will look at.
However, Mr Sunak told science reporters during a visit to Warwick University that the fusion industry said “loud and clear” it did not want to associate with the programme.
“So part of our research community said that there are bits of this that we would rather not be a part of because we think we’re better off having a bespoke UK scheme,” he said.
During negotiations, Downing Street insisted that a UK-based alternative to Horizon known as Pioneer remained on the table because Mr Sunak was concerned about “value for money”.
But the Prime Minister’s official spokesman denied that drawing up plans for that project had been a waste of civil servants’ time.
“All of their work, whether they were working on Pioneer or Horizon negotiation, has helped us negotiate a much better position than the one we were in,” he said.
The spokesman said the UK has “secured much better financial terms, protections and transitional arrangements” for Horizon.
He did not rule out Britain making financial contributions to rejoin other EU institutions, such as border agency Frontex.
European Commission president Ursula von der Leyen, who signed off on the deal with Mr Sunak on a call on Wednesday, said: “The EU and UK are key strategic partners and allies and today’s agreement proves that point.”
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 climate change, medical advances and artificial intelligence.
Months of negotiations between London and Brussels on Britain’s return followed the signing of the Windsor Framework deal, which was agreed in February and designed to address concerns over post-Brexit arrangements in Northern Ireland.