How would leaving the EU affect sovereignty?

Sovereignty is the main issue set to dominate the EU referendum campaign, but how much does the EU limit Britain's ability to make its own choices? How does EU membership constrict Britain’s ability to have decisions taken, policies set and laws made?
If the UK left the EU, parliament would have more power as it is a powerful institution within the UK, law can be passed without consultation with the EU and and sovereignty would increase.

If the UK left the EU, even though sovereignty will increase it may also spiral out of control. It would mean parliament would have complete power over the UK and pass and create any laws they want, without being stopped by the EU. Consequently, more mistakes can be made and the people may disagree with decisions creating lack of trust in politicians,

If the UK stayed in the EU, sovereignty will remain with the EU and there will be some control over what is passed by parliament. This gives opportunity to amend law if they are not suitable for the people of the country.

In conclusion, if the UK left the EU it could enable laws that benefit the UK as a country, instead of being dictated by what the EU want as it may be better suited to other countries within the EU. Therefore, the U.K. should leave the European Union and have ultimate power.