Keeping the lights on and the trains running after Brexit
According to the government, the need to ensure no hard border between Northern Ireland and the Irish Republic is central to the "big idea" contained in the latest Brexit White Paper - the development of a free trade area for goods.
The White Paper expresses the hope that if the EU agree to this proposition it will mean any legal text which the UK agrees in the future in order to underpin the Irish 'backstop' solution will not have to be used.
Some Brexiteers challenge this assertion, insisting that technology could have been used to overcome the problems posed by the border and minister should never have agreed to the "backstop" in December.
Repeating that argument, Jacob Rees Mogg told BBC Radio 4's Today programme that the prospect of a "hard border" is a complete "red herring".
If a "no deal" Brexit remains a possibility, the recent revelation by the Financial Times that barges could be stationed in the Irish Sea to keep the lights on in Northern Ireland sounds far fetched.
But it does graphically illustrate the range of concerns that must be addressed over the coming months in order to avoid widespread disruption.
On energy, the latest White Paper recommits the government to preserve the Single Electricity Market in Northern Ireland and the Republic of Ireland.
It also contains a slightly surprising requirement for a new British-Irish deal to keep the trains running across the border.
It says "the UK and relevant Member States have a common interest in ensuring that cross-border rail services, the Channel Tunnel and the Belfast-Dublin Enterprise line, continue without disruption".
Also on transport, in a section dealing with road hauliers, passenger operators and private motoring, the document says "the UK will ensure that there is no requirement in any scenario for new permits for transport services between Northern Ireland and Ireland."
The White Paper repeats previous commitments to the UK delivering its part of a future EU Peace funding programme, and looks forward to "a security partnership with the EU, including Ireland, that will allow the Police Service of Northern Ireland to continue to tackle security threats, including the severe threat from dissident republicans, and serious and organised crime."
There is an expression of hope that a future extradition system will build on any arrangements agreed for operating the European Arrest Warrant during a transitional Brexit period.
There is also a reference to the government commitments under the Good Friday Agreement to ensure the Irish language TV channel TG4 can be seen across Northern Ireland.
On the recognition of professional qualifications between people in the UK and the EU after Brexit the White Paper acknowledges "this is particularly relevant for the healthcare, education and veterinary/agri-food sectors in the context of North-South cooperation between Northern Ireland and Ireland."
The White Paper makes clear that the UK is leaving both the EU Common Agricultural Policy and the Common Fisheries Policy. But it underlines the fact that in relation to animal health the island of Ireland is already different in a number of important ways.
The government blueprint says the proposal for the UK and EU to maintain a common rule book on agri-food products "would remove the need to undertake additional regulatory checks at the border - avoiding the need for any physical infrastructure, such as Border Inspection Posts, at the border between Northern Ireland and Ireland".
The document notes that "Northern Ireland and Ireland form a single epidemiological unit.
The UK is fully committed to ensuring that the Northern Ireland Executive and North South Ministerial Council can, through agreement, continue to pursue specific initiatives, such as the All Ireland Animal Health and Welfare Strategy."
Whether the big free trade area for goods idea will survive the scrutiny it will face from the EU, Brexiteers and even Donald Trump remains uncertain. However the numerous references in the White Paper to Northern Ireland emphasise the complexity of the problems the negotiators on both sides are grappling with.