As a British man, running an international eCommerce company, I sit here in Berlin thinking a Brexit would be crazy! Short-term it would make it harder for UK e-tailers to reach mainland Europe’s 342 million internet users. In the medium-term leaving the EU would be a disaster for UK eCommerce and internet brands who want to compete in a global market. And long-term UK companies will be killed by those that grow up in the big markets of the US or EU, who have all the resources to beat UK brands.

The EU is a huge market on the UK’s doorstep and although the British appreciate the trading opportunities, the size of the market doesn’t get enough recognition. The EU is now Britain's largest trading partner, with over 51% of British exports of goods currently destined for its European partners. For e-retailers that is only a bit of translation and click away.

Napoleon, called the British “a nation of shopkeepers”. I don’t think he meant it as a compliment, but we should see it this way; we are good at it. The UK has solid retail brands respected by Europe and a highly entrepreneurial character in EU terms. And yet, just when we can become “Europe’s shopkeepers” we are thinking about excluding ourselves in a way that Napoleon could only have dreamed of.

Yes, the UK might be able to renegotiate a trade agreement, but politics and diplomacy do not move at the same pace as eCommerce. It could take years to get an agreement and why should Europe care? You’re either in the party or out; if you don’t want to be in the party, why should we save you some cake?

For e-tailers, the penetration of internet use across the EU makes it a very important, mature market. Leaving the EU would make it much harder for British eCommerce companies to compete on a global scale and bring long-term disaster.

This vote is also happening just as the Digital Single Market legislation is working its way into being. The UK media tends to cover EU initiatives that bring in red tape, waste money or are a complete waste of time. But here is one that has exactly the right objectives; to make it easier for a European business to work well in other EU states.

It aims to make cross border eCommerce easier, shipping more efficient, simplify VAT and provide a more up-to-date framework that is fairer across Europe. This is a good example of trying to get it right.

UK e-retailers need to get their head around this fast. In particular, they need to take note of the intention behind the Internal Market Clause. This includes the principle of ensuring that providers of online services are subject to the law of the member state in which they are established, and not to the law of the Member States where the service is accessible. This means you do not have to learn the laws of all the various EU states, but understand your own home regulation

It also will set out basic rules for eCommerce that acceptable everywhere. Currently at Spreadshirt we sell in 14 EU states and this is about to become much easier. All EU e-tailers will be operating in a larger, frictionless market, making their products easier for the European consumer to buy. This will be a boom to the EU eCommerce market.

Still want to Brexit? If the UK votes to leave, British e-tailers risk being left in the cold in the eCommerce stakes, becoming a relatively small and different regulation state. Those of us still in the EU will grow in a less complicated and more exciting market.