The government requires all EU nationals living in Britain before December 31, 2020, to register for a new immigration status managed and verified entirely online.
The government declined to comment on the reports about the departure of the flight over concerns about the safety of the relocating Afghan translators and their families.
The coronavirus pandemic has masked the economic dislocation caused by the referendum verdict, which backed severing five decades of integration with the European mainland.
Capable up to 290 kilometres per hour (180 mph), or six times faster than conventional ferries, the electric-powered craft cut emissions to essentially zero.
The G7 chiefs will be joined over the weekend by the leaders of Australia, South Africa, South Korea, the United Nations and European Union, with India joining remotely.
"But when they abandon enemy ranks and opt to live as ordinary Afghans in their homeland, they will not face any issues (and) hence they should not remain fearful."
Biden's administration is pushing for a 15 percent global minimum corporate tax that aims to resolve the issue of corporations sheltering profits in low-tax nations.
On the eve of the election, the United States, Britain, France, Germany and Italy said the poll was "neither free nor fair", and Syria's fragmented opposition has called it a "farce".
With known global infections approaching 163 million and the rise of new variants complicating the fight, even the governments easing closures are warning citizens to remain careful.
The goal is to find a way back to the accord known by its acronym JCPOA, which former US president Donald Trump walked away from and which his successor Joe Biden wants to revive.