They transport goods from Europe to Britain, export British produce to the EU, or recruit scientists and researchers... AFP has spoken to six people whose lives will be directly affected when Britain leaves the EU's single market and customs union on December 31.
- Dimitar Velinov, lorry driver -
A truck driver with many years of experience under his belt, Bulgarian Dimitar Velinov, 74, says he is expecting long queues at the UK border from January 1.
"To me, Brexit means logistical chaos, which will hinder our work," he explains in the garage of his employer Eurospeed, based in the outskirts of Sofia which employs more than 300 drivers.
"I transport goods across the European Union and for me it is important to be able to do my job without problems, without having to wait at borders for one or two days," Velinov says.
Crossing the Channel was already difficult as for years migrants have tried to stow away illegally in lorries heading to Britain.
But Brexit will make it even more so, the driver says, complaining that he gets no sleep at all while waiting to embark from the French port of Calais to avoid heavy fines for those found carrying stowaways.
- Sam Crowe, fisherman -
"We want to leave, 90 percent of fishermen want to leave," says 26-year-old Sam Crowe from Scarborough in the north of England.
"I still do feel like we are left in the dark a lot for what we do. The fish that we land and the scallops and the shrimps, all that is the freshest food on this planet and we're not praised enough for what we do," he says.
Crowe, who principally catches crab in the North Sea for export to Europe and China, says he has been heartened to see UK politicians fighting for the fishing sector in negotiations. As talks came down to the wire, European access to UK waters was a key sticking point.
"I've heard that they've been fighting for our quotas and obviously I am grateful for that," he says.
The fisherman feels the UK fishing industry will be given a new lease of life following changes expected to quotas that came with EU membership.
Fishing communities, like Scarborough where Crowe's family have fished for generations, have been in decline for decades. They hope Brexit will bring about a regeneration of their way of life.
"Back in the day the harbour was full of people to welcome in the lads and help out," Crowe says. "It's just not like that now. Nobody's interested."
- Greg McDonald, entrepreneur -
"Brexit was never good news for the British economy," Greg McDonald the chief executive of Goodfish, a small company that produces plastic parts for the automotive, medical and electronics industries, tells AFP.
"I closed a factory in March because our American customer closed their operation in the UK," he says.
McDonald's company is located in the heart of England's Midlands in Cannock, not far from Birmingham. It is also highly dependent on the EU and exports a large part of its output to the bloc.
"It's probably cost us half a million pounds (548,000 euros, $668,000) and 20 jobs" out of a total workforce of 110, he says.
The entrepreneur slams Brexit as a "political project driven by nationalist and populist governments" and questions whether those who had voted in favour of leaving will ever benefit from it.
McDonald says he had hoped for "minimum tariffs or no tariffs" when Britain left the EU and he complains of "more paperwork" and likely "problems at ports" after December 31.
- Pascal Aussignac, restauranteur -
"I have become a British citizen, but the company to which I have dedicated two decades of my life is no longer safe here and I am afraid of the future," says Pascal Aussignac, a French chef who has lived in London for 22 years and co-owns six premises, including a Michelin-starred restaurant and a cocktail bar.
"2021 could turn out to be worse than 2020. Are we going to survive? That's the big question," he says. Over the course of the year, he has already suffered the shock of the coronavirus pandemic and was forced to close for months.
He is also already feeling the effects of Brexit, which has already sparked a drain on the European employees needed in kitchens and restaurants.
British people don't work in the hospitality sector," Aussignac says.
The ability to continue to source the local produce from France on which he has built his reputation remains uncertain.
"I have no idea how long it will take to deliver" after January 1, he says.
- Tara Spires-Jones, academic -
Neuroscientist Tara Spires-Jones, from the University of Edinburgh, is concerned about international collaboration between laboratories, which she says was "very easy" with membership of the European Union.
"The changes of regulation, if it diverges from the EU, will be more difficult to share things like brain tissues and living cells," says the academic who is also the director of the British Dementia Research Institute.
"From day one, we will have more difficulties with ordering things, such as equipment," she cautions.
The researcher explains the end of the Brexit transition period will pose a "big problem" for British research funding, which is heavily subsidised by the EU.
"In our university, something between 20 and 30 percent of our research funding is coming from Europe," she says, noting there were no plans to replace this funding at the moment.
Though "no one will be fired on day one because of Brexit," some of the contracts of the 10 people she employs will not be renewable.
"It's a real threat," she says, warning there would also be an inevitable brain drain as European students stay away from Britain.
- Wendy Williams, homeowner in Greece -
Wendy Williams, a 62-year-old Briton, says she feels her "EU citizenship was stolen" by the Brexit vote.
As of January 1, she and her husband will not be able to travel as freely as before to their house on the Greek island of Kefalonia, bought in 2018 with all their savings, in anticipation of a retirement in the sun.
Unless they have a residence permit or a long-term visa, British citizens will now only be able to visit the European Union for a total of 90 days over a six-month period.
"We will have to calculate the days, and include any days spent elsewhere in the EU," she says.
"We had planned to spend longer periods in Greece," Williams says, but now they will only be able to spend a quarter of their time there.
While she continues to work in the UK, where her elderly father is also based, Williams said she will not embark on the process of obtaining a two-year visa for her family, a process she describes as "complicated" and "expensive".
"I am determined not to sell our Greek home but it is going to be difficult to get the benefit from it that we had hoped for," she says.