There's a big argument going on about this. It is mostly between these two groups of people.
These are people who think that getting more closely involved with Europe is a bad idea.
Some Eurosceptics feel that the UK is different from other European countries.
They are often worried that the UK is losing its independence and identity.
They think being in the EU is a good idea and often want the UK to start using the Euro currency.
Pro-Europe people think Britain will benefit from being part of a larger group of countries.
They often argue that Britain is in danger of being left behind by the rest of the EU if it doesn't join the Euro.