What is the likely effect of Brexit on the UK economy?

Less free trade with EU

The European Union is an important source and target for inward investment. Many European companies have invested in the UK and the UK earns revenue from investment in the EU. If the UK leaves the EU, this investment may be less attractive causing foreign firms to return to within the EU border. Companies like BMW has already warned workers of potential job losses in the case of a Brexit (1)

Fall in economic growth