A report by the technology recruitment platform Hired.com shows that the tech workers and employers in the UK are already seeing the effect of Brexit, with the number of foreign tech workers in the UK already down 50 percent.
Mehul Patel, CEO at Hired told Techworld that he was surprised with "just how quickly both demand for foreign workers and their interest in working here changed".
"So you have both sides feeling like it is uncertain what it is going to be like to be a foreign worker here or to hire someone and they are throttling their activity as a result."
As well as the 50 percent drop in foreign workers in the candidate pool on the platform since the decision to leave the European Union, the rate at which foreign tech workers are accepting UK-based roles has also decreased by nearly 20 percent.
Leave voters may be heartened to see the percentage of British companies sending offers to candidates outside the country fell from 25 percent at the beginning of 2016 to just 18 percent a year later.
The report also showed that the number of individuals accepting initial job offers from companies in the UK was down nearly 20 percent for foreign workers, whereas the acceptance rate was flat for local candidates.
The total sample size for the report was from 20,000 interview requests and job offers over the past year through Hired’s total UK marketplace of 850 companies and more than 100,000 job seekers.
This report comes at a time when the UK government has called a snap general election in the run-up to the hard task of negotiating an exit from the EU.
Anxiety about Brexit in the tech sector has been high since the referendum results came out, and the Hired survey of more than 200 UK-based tech workers exemplifies this. When asked what they were most worried about, the "impact of Brexit" was top with 55 percent of respondents, followed by happiness at work, personal development, economic uncertainty and salary.
With salaries already lower in the UK than other major tech cities across the USA and Australia, according to Hired, Patel sees Brexit as the potential tipping point when it comes to a highly-skilled tech worker deciding where they want to start a career.
Rival cities are already circling the UK's tech talent and businesses too. Just this week experts have predicted that the newly elected French Prime Minister Emmanuel Macron will look to poach talent to a more centrist France. Berlin deployed buses in the aftermath of the vote to urge UK startups to move to the German city.
The report showed that a startling 70 percent of UK tech workers have already considered leaving the UK, but Hired was unable to break that number out according to their nationality.
Patel qualified the findings by saying that the report is just a "pulse" for the UK jobs market post-Brexit and that the current period of uncertainty "might be the worst part of the curve".
"Once there is a better sense of what Brexit looks like, and if there is a hard Brexit which is looking likely, and what the immigration rules are going to look like, once people have a sense of that, you might see them get back to a new normal, but it will be a new normal, it won't be the old normal," he said.