The majority of small UK firms are worried about finding people with the right skills after Brexit, according to the Federation of Small Businesses (FSB).
A fifth of them currently have EU staff, and if Brexit were to create barriers to employment of EU citizens, some would consider moving abroad or scaling down operations, the FSB said in a report.
Though Prime Minister Theresa May had planned to take the UK out of the single market to restrict immigration, no agreement had been reached on protecting the rights of the millions of people from EU countries currently living in the UK.
Capping migration could worsen the skills gaps that the economy faced already. Also, if a deal on EU citizens' rights was not reached, businesses could face a ''sudden cliff-edge preventing small firms from accessing the workers they need,'' the FSB's chairman Mike Cherry said.
According to the FSB report, only 21 per cent of small firms currently employed staff from an EU country, but of those, 59 per cent were concerned about their ability to recruit the right staff in future.
According to the FSB, securing the right of EU staff to remain in the UK was vital. According to Cherry, small firms feared they would lose skilled staff who would be difficult to replace if this was not done.
"EU workers are a vital part of our economy, helping to plug chronic skills gaps across a wide range of sectors, and filling jobs in an already tight labour market," he said.
"From packers, to mechanics, to graphic designers, small employers need to be able to hire the right person, for the right job at the right time."
According to commentators, the right of EU and non-EU citizens to come and work in the UK, after Brexit, was still entirely unclear.