The European Union (EU) is a guarantor of peace, stability and not least of prosperity in Europe. It provides invaluable benefits for Germany, its citizens and its companies, especially access to the EU internal market, which forms the foundation of the EU.

The EU internal market is the world's largest single market. Its principle is quite simple: it guarantees free movement of goods, services, capital and people for all citizens and companies in Germany and throughout the EU. Within the internal market, EU citizens can live and work in other EU states, and enterprises can freely produce and sell their goods and services. A German citizen, for instance, can open a travel agency in Belgium and have a bank account at a Dutch bank. EU-wide standards have made products such as pharmaceuticals safer for consumers. Furthermore, prices - for example of flights or mobile phone calls - have fallen considerably.

Our export-oriented economy is also benefitting from the European internal market. German companies can import goods from and export products to other EU states without tariffs. The share of Germany's trade with other EU countries has risen to almost 60 per cent. This shows that without the EU internal market the German economy would be far less successful than it is today. For more information about the history and the functioning of the internal market, click here.

But the EU is more than that: it is also a community of fundamental rights and values. The EU Charter of Fundamental Rights entered into force at the end of 2009. It contains a binding catalogue of citizens' freedoms and fundamental rights and sets out the economic and social rights guaranteeing individual freedoms, prosperity and social justice for citizens and enterprises.

After the UK's referendum on a possible exit from the EU, we must make the key promises of European unity, including peace, democracy and prosperity, more visible and fill them with new life. We must conduct a constructive debate for a better Europe. In particular, we must overcome the employment and investment crisis in Europe so that Europe can provide more economic and social stability in the future.