Potential problems for people and some goods crossing the border between Gibraltar and Spain have been spelled out in detail recently through two Technical Notices issued by the Gibraltar government.
The first document explains that if there is no agreement which covers the future relationship of Gibraltar with the European Union, the situation at the border will change considerably because British nationals will be subject to the same controls as those from other non-EU countries. This means their passports will have to be stamped every time they cross the border in either direction, and their documents scanned into the Schengen Information System.
People crossing from Gibraltar into Spain would only be able to spend 90 out of any 180 days in the Schengen area, and could be questioned about the reasons for their visit and whether they have the means of subsistence while they are there.
Also, from 2020, the ETIAS travel pre-authorisation system would apply.
In terms of goods crossing into Gibraltar, those from the EU will not be affected because Gibraltar is not in the Customs Union and they already have to pass through a hard border to get there. However, some goods coming to Gibraltar from the UK, namely those of animal origin, would be subject to EU rules which say they have to be checked upon entry to the EU and again when they leave. This means that these goods would have to be checked at the existing Border Control Post (BCP) in Algeciras, Spain, and then transferred to Gibraltar by ship.
These changes, which affect people and goods, could result in long delays, which Gibraltar is keen to avoid if possible. The government is holding talks with Spain and the EU about ways of doing this, including the possibility of being part of Schengen, but one problem with that is that Spain says it wants to control entry points to Gibraltar and the Gibraltar authorities say having Spanish officers on their territory is a line they are not prepared to cross.
The talks continue, but an awful lot of people currently have their fingers crossed.