These are the nine Brexits that lie ahead – but Article 50 will only deal with one of them

From the single market to our border with France, the Article 50 negotiations will fail to address some of the most critical elements of the Brexit process

Negotiations between German Chancellor Angela Merkel and British Prime Minister Theresa May over Brexit won't cover every effect of the process for Britain (Reuters)

When Prime Minister Theresa May repeats her favourite incantation – “Brexit Means Brexit” – what does she actually mean? As Whitehall struggles to come up with a plan for Brexit, and hires an extra 30,000 civil servants to prepare for life outside the EU, it may be more helpful to see Brexit not in the singular but as a plural concept. There are many separate Brexits that can be identified.

1. Political Brexit
This the end of the UK’s formal participation in the European Union. No more commissioners, no more MEPs, no automatic transmission into UK law of EU directives. Only the House of Commons will decide how Britain is governed after Brexit.

2. Single market Brexit
This is the end of full unfettered access to the EU’s single market of 450 million customers. It is possible to be outside the political EU but stay in the Single Market like Norway and Switzerland.

3. Customs union Brexit
Leaving the EU customs union would require every good or components in goods destined for sale in Europe to be customs cleared. Turkey is not in the political EU, but is in the EU customs union.

4. Frexit Brexit
Alain Juppé is the latest of the French centre-right candidates looking to succeed François Hollande to insist that our border with France be moved to British soil.

5. Free movement Brexit
Ukip and the Conservatives have made the number of EU citizens in the UK a number one domestic political issue this century. Imposing a cumbersome bureaucracy of quotas, seasonal work permits, travel visas or regional work permits, such as a passport stamp for the City, will be expensive and alienate other governments, who will resent such discrimination against their voters.

6. Geo-political Brexit
For the Kremlin, seeing Europe revert to disunited nation states has been a long-standing strategic goal. As Donald Trump’s election rhetoric risks the US reverting to neo-isolationism too, can Britain retain a global role if utterly disconnected from Europe?

7. Policing and security Brexit
Can the UK stay in the post-national networks of information exchange and policing once Britain has left political Europe? We don't know.

8. Environmental Brexit
Many (though not all) pro-Brexit Eurosceptics are also climate change sceptics. Does the UK give up its leadership role in shaping environmental politics in Europe when it leaves the EU? British ministers and elected politicians will certainly no longer play a role in EU policy-making.

9. Expat Brexit
There are an estimated two million Britons living, working or retired, in other EU member states – with a concentration in nearby EU nations such as Spain and France. In Spain, a non-EU citizen who wants to drive must pass a practical and written test in Spanish. British expats may see their present and future rights evaporate as Britain turns against European citizens in the UK.

There's also the possibility of one more: a human rights Brexit. May says that British judges must now decide all British law and the European Court of Justice – largely a commercial and administrative tribunal should have no place in Britain. But it is the European Court of Human Rights linked the Council of Europe, set up by Winston Churchill, which is the supranational court which most imposes its rulings on British judges. So after political Brexit from the EU, does a Brexit from the ECHR not logically follow? We'll hear more from our Prime Minister on that next year.

So there are many types of Brexit that will have to be debated and decided. The impact of Brexit on our close neighbour Ireland is enormous and as yet unmeasured. The Article 50 negotiations which are due to start in March 2017 and will last two years deal narrowly with political Brexits. All the other Brexits will take years to finalise.

Denis MacShane is the former minister for Europe and the author of 'Brexit: How Britain Left Europe', published by IB Tauris