With all the political drive to achieve Brexit as soon as possible, a simple fact is often missed. Once Brexit happens and we have left the European Union, that is it. There is no going back, even if we quickly realise we have made a terrible mistake. Quite simply, Brexit is not a trial separation.
A legal judgement has been made that up to the moment of leaving the EU, we can cancel our intention to leave. We can revoke the Article 50 Notification, and retain all the existing special conditions and opt-outs we currently enjoy. But once we have actually left, there will then be no possibility of our changing the decision, even through a People’s Vote. For this reason, it is of vital importance that the full implications of leaving the EU are understood by all involved. There is no hiding the fact that, if the British people are to have a say, this must happen while this country is still a member of the EU.
Once out of the EU, even if in a close relationship such as a customs union, Britain would be regarded as a “third country”. Any application to rejoin would be a long and difficult process, with no guarantee of success. We would need to join the queue of what is known as “accession countries”, currently including Serbia, Montenegro and several more.
Strict tests would be applied, almost certainly including a commitment to join the euro and Schengen area (no border controls). Our current opt-outs will have lapsed on giving up our membership, as would the highly valued budget rebate negotiated by Mrs Thatcher. The EU would want to be convinced that the UK was fully committed to the work of the European institutions, and would no longer be seen as a reluctant or semi-detached member. Britain’s re-entry to the EU would need to be approved by all the existing member countries, any one of which would have a veto. Further concessions might be demanded, such as changes to the status of Gibraltar, that could be unacceptable to the UK.
Overall, leaving the EU is not simply resigning from a club, that we could easily rejoin if we changed our mind. It is an irreversible change, giving up for ever our hard-won special terms of membership. An application to rejoin would involve challenging and uncertain negotiations extending over many years; we would be definitively out for a generation or more. Giving up all this is not a decision to be taken lightly.