#Brexit: Special Administrative Region status for London, Scotland and Northern Ireland?
Could London, Scotland and Northern Ireland become Special Administrative Regions (SARs) of the UK allowing them to set their own terms of trade with the EU?
The not so barmy idea was suggested to me by a close friend and former international commercial lawyer.
The most obvious example of such an arrangement is Hong Kong.

In anticipation of the British handover of Hong Kong, China updated their constitution to provide for SARs to be set up as their answer to the vexing question of Hong Kong sovereignty post-handover.
Given the UK government was party to the agreement there could be a basis in law for London, Scotland and Northern Ireland (and other areas - something will have to be done about Gibraltar) to gain greater autonomy, particularly on the issue of trade and immigration with the EU.
Special Administrative Regions of China:
"continue to possess their own governments, multi-party legislatures, legal systems, police forces, monetary systems, separate customs territory, immigration policies, national sports teams, official languages, postal systems, academic and educational systems, and substantial competence in external relations that are different or independent from the People's Republic of China."
UK versions may not have to be so drastic but the important bit is the power over external relations.
While China still retains defence and foreign policy, Hong Kong (and Macau the other SAR) has a great degree of autonomy in the latter through trade policy:
"Special administrative regions are empowered to contract a wide range of agreements with other countries and territories such as mutual abolition of visa requirement, mutual legal aid, air services, extradition, handling of double taxation and others. In diplomatic talks involving a SAR, the SAR concerned may send officials to be part of the Chinese delegation. In sporting events the SARs participate under the respective names of "Hong Kong, China" and "Macau, China", and compete as different entities.”
With Scotland itching to leave the UK and remain part of the EU, Northern Ireland already having a special status by default of its history and London being an international city with a financial services sector dependent on continued EU membership - could SARs (or some kind of SARs-lite) be a way for all to get what they want (remaining linked to the EU) while the rest of the country goes its own way?
If you're thinking this is a ridiculous suggestion because Parliament is based in London. The building is crumbling and needs to be evacuated for repairs, there is talk of the UK government temporarily moving out of London at some point soon.