Thousands of companies in London and the South East are likely to collapse in the event of a no - deal Brexit , with more than 66,000 job losses predicted in London , according to business intelligence website Populous . World . Even if a deal is struck , 7,900 UK companies are expected to fail , with 41,800 jobs lost . Small and medium - sized firms are expected to be hit hardest , with closures potentially outnumbering start - ups for the first time since 2009 . However, if Theresa May fails to reach terms with EU leaders and Britain crashes out of the bloc in March, the total rises to 12,540, with 66,245 jobs lost. The number of businesses closing in London in the year following the 2016 EU referendum dropped 14 % .
Thousands of companies in London and the South East are likely to collapse in the event of a no - deal Brexit , with more than 66,000 job losses predicted in London , according to business intelligence website Populous . World . Even if a deal is struck , 7,900 UK companies are expected to fail , with 41,800 jobs lost . Small and medium - sized firms are expected to be hit hardest , with closures potentially outnumbering start - ups for the first time since 2009 . The number of businesses closing in London in the year following the 2016 EU referendum dropped 14 % .