In 1973 Britain joined the EU meaning that they are protected from imports from abroad. For example if a firm in America wanted to import a product into the UK then they would have to pay a sum of money or a tariff. In the EU there is a rule that means that all members can trade freely with one another inside Europe without having to pay tax or any money for the import or export of their goods. But before 1973 Britain's industries were very poor and there was no reason why the government should do anything about it. Competition was low and this is why they did not.
Britain originally joined the EU for economic reasons mainly to gain the advantage of having a free trade area. As soon as Britain did join they faced a big threat. The quality and output of goods in Britain was poor even though they provided for the rest of Europe, this meant that the firms making could fall behind and run out of business if they did not improve. Not only could Britain's products now improve they were now under protection from abroad. One other advantage that the EU offered for Britain was the free movement of workers in Europe.
If someone from France wanted to work in Britain they could but if Britain had not been in the EU then they would not have been able to. The real advantage of moving workers freely from one country to another is that these workers will be highly skilled. For example, Belgium is renowned for its ability to make quality chocolates but British chocolate is not to the same standard. Britain is generally better at making cars than Belgium. It would be a disadvantage to these countries if they tried to improve what they are not good at.
A lot of time and money would have to be put into these industries diverting attention away from what really matters. However, if the Belgian chocolate workers moved to Britain and the British Car makers moved to Belgium then each country can improve. It is thought to many people that these workers who come into the UK are asylum seekers and cost many ordinary British citizens their jobs. This is not true as these workers are highly skilled and do not seek asylum in Britain. This can be proved by the growing number of foreign workers who become say brain surgeons and professors.
These people do not cost jobs because they cause industry to be pushed to keep up with the amount of people working in Britain. If it was true that foreigners cost jobs it would mean that every time a baby is born a job is lost and this is ridiculous. In fact without these free movement of labour industries would not grow. When Britain joined the EU in 1973 although countries belonging to it were not allowed to introduce tariffs to goods they subsidised or used a quota. A quota is a limit on the amount of imports per year.
If Britain was importing Beer from Germany then they could say that only so many thousand galleons of the Beer is allowed to enter the UK in one year. Ireland did this effectively once when the government said that only butter in round tubs was allowed to be imported. It was also possible to say that goods had to live up to a certain specification or they could not be brought into the country. But by the 1st of January 1993 the UK was required to get rid of any subsides, quotas or technical specifications.
If Britain did leave the EU then they would lose all of this and more. There would be no free movement of workers and because of this a labour shortage would not be able to be relieved. In the opinions of some countries we would no longer qualify for being European and this would not help Britain's reputation as it does not see eye to eye with some European countries at the moment. In fact the only real advantage of leaving the EU is that free trade is still available. This is because it is recognised throughout Europe that free trade is the best solution for both parties.
But seeing as this would happen if we were in the EU anyway there is really not much point. But recently many important figures around Europe including Tony Blair are discussing a new currency for most of Europe, the Euro. This is a disadvantage to everyone because it means for one thing that if there is a crash or recession then there is the possibility of everyone else falling into the same trap. But is does have the practical advantage of no exchange rates and easier finance.
My opinion is that Britain should not leave the EU because they gain much more if they stay in it. If each country specialises in different industries then trades freely with one another they will all be more efficient. This is why France makes good wine Belgium chocolate, UK cars and so on. This is why it is important to stay in the EU, because we are relying on others and others are relying on us. Britain will gain nothing from leaving the EU except possibly escaping from the Euro which many people are against.