Registering more than 3 million EU migrants already living in Britain would be a massive administrative task for the government, a report from Migration Observatory says.
Experts from the Oxford-based study centre looked at the existing regime for applying for permanent residence to examine possible issues that could arise if any new system was introduced following the Brexit vote.
Their analysis suggests that if all the European Economic Area (EEA) citizens living in the UK at the beginning of 2016 applied for permanent residence in the same year, this would amount to the equivalent of around 140 years of work at recent rates of processing.
Madeleine Sumption, director of the Migration Observatory, told the Guardian: “Depending on how long Brexit negotiations take, the government may need to register EU citizens already living here quite quickly.
“Given the sheer number of EU citizens who would need to register and the potential complexity of the process, this will be a formidable task.”
The Observatory looked at the existing regime through which EU nationals apply for permanent residence. Under the rules, those who have lived continuously in the UK for at least five years automatically have a permanent right to reside.
Assuming free movement comes to an end after the exit process is formalised, EU citizens may need to obtain documents demonstrating their residence rights within a relatively short period of time.
That would distinguish them from newly arriving EU citizens who do not continue to enjoy free movement rights, according to the study.