When the EU referendum result was announced Vera Troeger, professor of quantitative political economy at Warwick University, was at an academic conference in Brussels. She spent the whole day crying. Today she has had enough, and is leaving the country where she has built her career.

Troeger, an expert on the gender pay gap and the impact of parental leave policies on productivity, was associate editor of one of the most highly ranked academic journals in political science. She has been in the UK for 14 years and loves Warwick, but she has accepted a professorship at the University of Hamburg. After more than two years of uncertainty, she says other European colleagues, too, are preparing to go.

“I have a lot of academic friends over here from Spain, Italy and France, and they have all congratulated me on leaving all this behind,” she says. “Of course the academics who will be able to leave are mostly the successful ones. It will be a brain drain.”

Last week Universities UK, the vice-chancellors’ body, criticised the government for failing to provide enough protection for research in the event of a no-deal Brexit.

The government pledged to underwrite awards from the European Union’s €77bn (£67bn) seven-year Horizon 2020 programme. But furious academics have discovered that while existing grants will be covered, there is no funding for new applications in the event of a no-deal Brexit.

Vivienne Stern, director of the international arm of UUK, says: “That has been a real shock.” She says normally the UK could expect to net €900m in the next 18 months from its share of ERC money, so universities will face a huge funding gap. But the researchers who win these prestigious grants are also “the best of the best” – and universities are terrified they will lose them.

“Many European researchers have been resisting an offer of another job abroad, and the temptation of a higher salary, because they want to work in the UK system. This will feel like a real kick in the teeth,” Stern says.

Troeger says her discipline relies heavily on funding from the ERC and the uncertainty is shaking researchers. Brexit feels personal. “I am struggling with the hostility there is towards experts in the UK now,” she says. “I am remembering Michael Gove saying people in this country have had enough of experts. I found that difficult to stomach.”

UK universities say competitors across the channel are stepping up their approaches to talented European staff. Exeter nearly lost three academics in law and politics to European universities in the past fortnight – but made swift counter offers. The university says another of its leading researchers has said they will move to an EU university with their ERC grant if there is no deal.

Andreas Goldthau, climate policy expert: ‘You get emails from headhunters and say no, but with Brexit you pick up the phone and start listening.’ Photograph: Daniel Vegel

Andreas Goldthau, a German professor of international relations and an expert in energy security at Royal Holloway, University of London, has accepted an offer in Germany because of Brexit. He is a leading figure in climate policy research, and the university says losing him means losing millions of euros of future EU research funding.

He said: “You get emails from headhunters and my answer has always been not interested, but at some point with Brexit you pick up the phone and start listening.”

Goldthau moved his family to Berlin shortly after the referendum, and has been commuting to London three or four days a week. “The UK leaving Europe leaves me in limbo, as that whole cross-border worker regime will be gone,” he says.

Like Troeger, he says Brexit feels personal. “My family is a European patchwork and the UK waving goodbye to a project that has made a lot of what I am possible has been very hard.”

He says academics have been relying on the government’s promise to underwrite Horizon 2020 grants, and there is “real anger” they will not all be covered. “But people are already being cut out of EU-funded research applications,” he adds.

Goldthau says modern researchers work in networks across countries and disciplines to solve complex questions. Before Brexit, he averaged one inquiry a month from an EU research team interested in collaborating on a funding bid for a research project. “Since the Brexit vote I have had none. Suddenly I was a risk. If I lead on a project, chances are it might not get done.”

Jurriaan Ton, a Dutch professor of plant science at Sheffield University, who has received considerable ERC funding, says Horizon 2020 is “one of the last strongholds for funding the sort of risky, unpredictable research that is so important in science”.

Ton, who leads a team of 14 researchers investigating how plants adapt to environmental stress, has been named as one of the world’s most highly cited researchers in his field. He is finding Brexit “unbearable”. “My partner is Irish, my son has a Yorkshire accent and I put vinegar on my chips. I love Sheffield and consider myself more British than Dutch now, but I will have to consider applying for another ERC grant at another European university if the alternative is trying to continue my research in a post-Brexit wasteland.”

Orazio Attanasio, an Italian professor of economics at UCL who has been in the UK for 22 years, has accepted a position at Yale, with Brexit helping swing his decision. In 2016 he was awarded the prestigious Klaus J Jacobs research prize for the use of economic models to shape child development programmes in poor countries. “It’s been two years now and still no one knows what Brexit means. That is incredibly frustrating,” he says. “I think if there isn’t a deal it is a reasonable assumption that a lot of European academics will decide to leave.”

Universities also risk losing young EU researchers – or failing to woo them. Lukas Esterle, an Austrian early career researcher who moved to Aston University with a prestigious European Marie Sklodowska-Curie fellowship, is relocating to Aarhus University in Denmark to escape Brexit.

“I have two young kids and my wife moved here too. There has been tremendous uncertainty for us. We go back to visit the kids’ grandparents as often as we can. It is unclear how easy that will be after Brexit.”

Esterle is researching adapting smart camera networks to track people and has been highly cited for someone so early in their career. “If I’d been applying now as an early career researcher I wouldn’t have come to the UK,” he says.

Simon Marginson, professor of higher education at Oxford University, says Britain’s capacity to “pick and choose” the best young researchers from the EU talent pool will be greatly diminished. His team interviewed academics at 12 universities about Brexit, and not one said it was good that there would be more opportunities for homegrown PhD students and junior staff. “The insular, nativist politics that has driven Brexit has no echo in universities.”

A government spokesperson said: “Science recognises no borders and the UK has a proud record of welcoming the world’s leading researchers. This will not change when we leave the EU. Through our modern industrial strategy we are investing a record level in research and development and we are committed to seeking an ambitious future relationship on science and innovation with our EU partners.”

• This article was amended on 26 and 29 March 2019: a previous version said Vera Troeger was going to work in Hanover; and the €77bn (£67bn) figure relates to the European Union not the European Research Council.