This question has been settled with a final result: "Extension of UK/EU negotiations". Trading has finished.
On June the 23rd, 2016 the British people have declared in a national referendum (Brexit) that they wanted to withdraw from the European Union. 51.9% of them have voted for “Leave”. For more background: Wikipedia
Now the British government formally has to notify the European Council of the UK’s intention to withdraw from the EU in accordance with Article 50 of the Treaty of the European Union. (1)
The new British PM Theresa May, who has replaced David Cameron on 13. July 2016, said her priorities will be to administer Britain's exit from the European Union. (3) Next, the UK and the European Union have to find a special agreement about their future relationship.
The following outcomes are possible:
Also it is still possible the UK does not notify the EU of its intent to withdraw from the EU. But the new PM May said: ""Brexit means Brexit, and we're going to make a success of it. There will be no attempts to remain inside the EU. No attempts to rejoin it by the back door. No second referendum." (3)