Since Britain voted to leave the European Union over a year ago, millions of EU citizens living in the U.K. and over a million British expats in other EU states have been living in a prolonged state of insecurity about their future. Ali Capper, who runs a 200-year-old fruit and hops farm with her husband Richard, told CNBC that the ongoing uncertainty regarding citizens' rights was reaching "crisis point." Capper explained the West Midlands farm typically employed around 70 seasonal workers from EU countries – such as Poland, Romania and Bulgaria – to help harvest crops each spring and fall. However, since the Brexit vote, Stocks Farm had found the recruitment process increasingly difficult. "While we're concerned about getting the numbers we need this year, next year we're very concerned. I mean with all the confusion and concern about status … Why would you choose to come to Britain?" Capper said in a phone interview. She argued the ongoing precariousness regarding citizens' protections; safety concerns amid an increase in xenophobic attacks and a weaker U.K. currency had all dented Britain's appeal among EU workers. Sterling has fallen by around 16 percent against the dollar and 18 percent against the euro since the night of June's referendum. "We're reaching crisis point for all businesses, we need to know what is happening and this is true whether you're running a business in care, construction or farming. There's just no clarity at all, we've not moved a single step further forward since the referendum," she added. The first hurdle for Britain and Europe during formal Brexit talks is to agree on the rights of EU citizens in Britain, and of U.K. citizens in the EU, with both sides calling for an urgent resolution in order to resolve any lingering uncertainty.

Britain was recently found to be the most attractive place to relocate among EU workers – according to a Deloitte survey published at the end of June – thanks, in large part, to the country's cultural diversity and promising job prospects. The consultancy firm surveyed more than 2,000 EU and non-EU workers, half living in Britain and half living outside, and found 57 percent of respondents would be prepared to move to the U.K. given the opportunity. However, the same survey found that more than one third of non-British citizens working in the U.K. said they had considered leaving the country, with highly skilled EU workers the most likely to move. Almost half of highly skilled workers based in the U.K were found to be thinking about leaving in the next five years with 65 percent describing Britain as a "less attractive" place to live since the Brexit vote.

'Lifeless pursuit' for British citizenship

A protester draped in a European Union flag takes part in a protest in support of an amendment to guarantee legal status of EU citizens, outside the Houses of Parliament in London on March 13, 2017. DANIEL LEAL-OLIVAS | AFP | Getty Images

Axel Antoni, a 43-year-old German national who has been living in the U.K. since 2001, told CNBC that the ongoing uncertainty had forced him to apply for British citizenship. "Becoming British should be a joyful process … Something which you relish doing because you can prove just how much you love the country. Instead, it is becoming more of a lifeless pursuit and I am really only doing it because I feel I need to do it to secure my legal status," the business consultant said in a phone interview. Antoni is also the spokesperson for the3million, a lobby group that represents the views of EU citizens living in the U.K. Residing just west of London in Windsor with his British wife and two dual-nationality children, Antoni quipped that you don't end up living in the U.K. for nearly 17 years if you hate the country. However, he described his time in Britain since the EU referendum last year as "stressful". "The problem I have, and by the way it is the same for millions of other people, is that we have had 13 months not knowing what will happen, when it will happen and how it will happen. And the more I hear in the news, the more I worry," he added.

'Moral imperative' to resolve citizens' rights

Chief negotiator for the European Union, Michel Barnier (R) and Secretary of State for Exiting the European Union, David Davis (L) hold a joint press conference during the second round of the Brexit negotiations in Brussels, Belgium on July 20, 2017. Dursun Aydemir | Anadolu Agency | Getty Images