The BBC claims that globalization is the primary driver of Britain's economic problems including decisions made when it was part of the EU. As a result, the percent of the workforce involved in "making stuff" dropped from 55% to 9%.
It will take deliberate actions to rebuild its economy and rely less on other countries for Britain to regain its economic growth. England will need to re--industrialize and that will require favorable tax policies (not allowed under the EU).
I believe Britain can and will change its stars, but the first step will be to reduce entitlements and replace them with jobs that "make stuff". It must then like Germany focus its educational system at producing the talent to fill those industrial jobs.