"Once article 50 is triggered the exiting nation is leaving unless every single other member state agrees otherwise. So the status of the UK would not be in the control of the British Government if people decided to reverse the referendum decision. In fact deciding that we will have a referendum at the end of the process effectively destroys our negotiating position. The EU doesn't want to lose a cash cow, the second largest net contributor to the EU budget. So they would have every incentive to offer the worst deal possible to try and encourage people to want to stay. They of course could then dictate the terms of our readmission. We could kiss goodbye to the rebate and other opt outs."

Some commentators refute the idea that article 50, once triggered, cannot be reversed - the simplest way of doing this: the formal procedure required at the end of the 2 years is just left to rot.