In the EU, because sovereignty is shared with other countries, Ministers and Civil Servants have had to negotiate and compromise and do deals to get things done.
The EU has increased the workload of Prime Ministers and Ministers who have to spend time negotiating in Brussels and has also tended to move power away from the Cabinet.
EU membership has reduced the legal power of the British Parliament, at least in areas such as competition and employment policy, environmental protection and food safety which are decided in the EU.
The United Kingdom needed to come out of the EU. The Nazis didn't lose WW2, they created the EU, which is the 4th Reich.