At the beginning of the twentieth century, the United Kingdom commanded a world-wide empire as the foremost global power. Unfortunately, the two world wars and the finish of realm lessened its part. Yet, the UK remains a monetary and military power, with significant political and social impact far and wide. (BBC News, 2018). However, even if Great Britain has an enormous and undiscussed relevance in EU, as the tallying of votes cast on June 23rd, about 52% of the electorates had voted in favour of Leave against 48% for Remain. Immediately afterwards, Nigel Farage, leader of the UK Independence Party, marked the Independence Day for Britain. (Economist.com, 2018). At the moment, the whole world is still unaware of the future consequences of this referendum on the British economy and above all, on small and medium-sized firms which actually represent the 99.3% of all private sector businesses at the start of 2017 with a total employment of 16.1 million; more than half of all private ownership in the UK (Fsb.org.uk, 2018). Furthermore, according to the European union evaluation, small and medium-sized enterprises (SMEs) represent 99% of all businesses in the EU (Crescita, 2018). Due to this big relevance, the referendum will definitely have effects on those; within the UK and in EU ecosystem. This essay explains whether SME will be affected by these big political changes and analyses the benefits and drawbacks of this decision to leave the European Union. One of the concern that has led to the referendum was immigration. In fact, The United Kingdom aims to cut the current annual flow of EU nationals coming to Britain introducing restrictions and new policies in order to cut immigration at “sustainable levels” in order to prefer British workers above all, under a detailed proposal set out in a Home Office document leaked to the Guardian. (Travis and Hopkins, 2018). The United Kingdom Is known as one of the most multi-ethnic country of Europe. In 2015, there were around 3.3 million EU immigrants living in the UK up from 0.9 million in 1995 – a rise to 5.3% of the population from 1.5%. (Anon, 2018). However, even if Brexiter are trying to do everything in their power, statistics and data have demonstrated the opposite needs than a policy to restrict immigration. This because due to the fact that immigrants consume local services and goods, this increases demand and so raises job prospects of those who produce those goods and services and also, with high skilled workers, company can increase their productivity with a consequently increase in wages. (Anon, 2018). In conclusion, especially regarding small and medium business, the immigration had and will have positive effects as a result of the reasons stated above.