Will Brexit spark a brain-drain for UK?

The shock result of the U.K.'s referendum on its future in the European Union has thrust the region into renewed uncertainty. One area of concern is how Brexit will impact job recruitment.

Many businesses are concerned about what the result, in which the vote to leave won 51.9 percent of support, will mean for their staff.

"The result is shocking and it's a sad day for the UK," Mark Mitchell, CEO of recruitment specialist Meridian Business Support, said in a statement.

"The result makes us appear to be less friendly and tolerant and has turned many of our workforce into official immigrants than colleagues – this will have a detrimental effect on staffing."

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EU nationals may now be nervous and reluctant to apply for jobs in the U.K., warned Siân Goodson, managing director of executive search and corporate insight business Goodson Thomas.

"My concern is to what extent will we now be able to attract EU candidates for prestigious roles in the U.K?" she said in a statement to CNBC.

"It wasn't an easy ask previously because of how the different member states' education systems were set up and because of the various EU rules and regulations, but it was always an option to include EU candidates in our listings."

The result could prove to be highly divisive. Several young people took to social media Friday to express their disappointment with the decision and considered emigrating, while U.K. nationals working abroad pledged not to return.

"I'll be staying in Spain now. Maybe elsewhere in Europe beyond that. But not the United Kingdom," Joey Vaughan, a bar manager from Kent working in Spain, told CNBC via email.

The main issue for businesses and the economy is uncertainty, as the U.K. will now have to engage in a two-year negotiation process to exit the EU.

"One possible scenario is that in order to retain access to the single market, the U.K. would have to continue to accept the free movement of people from the EU. In this case little would change," Ian Dowd, director at NGA Human Resources, told CNBC via email.

"Another scenario would see restrictions of some kind on EU citizens, which could make it harder for some Europeans to work in the U.K."

Small and medium-sized businesses will likely find it harder to recruit post-Brexit, according to Eugene Mizin, CEO and co-founder of recruitment app Job Today.

"Access to talent will tighten, as fewer EU foreigners will enter Britain's workforce, which will drive up hiring costs," he told CNBC in an email. "As economic outlooks remain unclear, SMEs will look to spend less on recruiting and think twice before spending hundreds of pounds on job boards. Instead, SMEs will increasingly turn to referral and word of mouth hiring."

Other business leaders were less concerned and focused on the underlying strength of the U.K. economy.

"There will undoubtedly be short-term uncertainty in the labor market but the foundations of the U.K. economy remain strong and we remain confident that U.K. based business will continue to attract and retain talent from within U.K. and beyond its borders," Lee Rankin, managing director at recruitment firm GEM Partnership told CNBC via email.

However, rather than experiencing a brain drain of talent, the U.K. economy could become a more agile and attractive place to work.

"It depends on what path the U.K. takes – talent goes where the opportunity is, and Europe is the world's slowest growing continent, largely due to EU economic policies," Harrison Wright, managing director of Affinity Biotechnology, which specializes in biotech recruitment, told CNBC via email.

"If the U.K. takes the opportunity to make itself more attractive for business and easier for skilled workers around the world to immigrate, we will see the opposite of a brain drain."

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