The complexity of the police agreement makes it difficult to demolish the Gibraltar Frontier ("La Verja") after Brexit.

Year 2025. The Gibraltar Frontier ("La Verja") no longer exists. A network of entry and exit routes between La Línea and Gibraltar occupies the space where the customs buildings of the border crossing once stood. A speeding car enters Gibraltar through the access from Príncipe de Asturias Avenue, while the pursuing vehicle of the National Police stops in La Línea. It cannot enter. The criminal has escaped.

This hypothetical case has not occurred because the Verja (frontier) still stands, but it is one of the issues that has puzzled the negotiators of the treaty that will govern Gibraltar's relationship with the European Union after Brexit. They initially intended to demolish the Verja but encountered serious security problems in the region that they are trying to resolve. The invented case could also be posed in reverse. What happens if the Royal Gibraltar Police pursue a criminal who escapes to Spain?

In the first week of May, a technical meeting took place at Gibraltar Airport between police authorities from both sides to advance agreements for managing this and other security issues, which are separate from the control of people that would no longer exist at that location. Instead, control would be shifted to the port and airport of the Rock, as established by the New Year's Eve Agreement signed by Spain and the United Kingdom in 2020, which serves as the basis for the negotiation of the aforementioned treaty on Gibraltar's future relationship with the European Union (EU), particularly its neighbours in La Línea and the Campo de Gibraltar.

If the Verja were to fall, a flow of citizens would occur between the two cities across an imaginary line. According to sources close to these conversations, as Europa Sur has learned, the complexity is enormous and hampers the signing of the treaty itself. Instead, the idea of establishing a normative framework agreement is being considered, which would be further developed over time. In other words, a system that allows for solving problems as they arise and learning from the experience, once the new situation is in place.

Initially, if the National Police were pursuing a criminal who crosses that "imaginary line" into Gibraltar, the Spanish authorities would have to request extradition. And it would be to the United Kingdom, not Gibraltar, as Spain does not recognise it as a separate state. Three jurisdictions would be involved in each case: Spanish, British, and Gibraltarian, which would open a bureaucratic process that could take months, perhaps more than a year, rendering it ineffective. Finding a solution to this hurdle and including it in the articles of the treaty is "practically impossible," according to the same sources.

The Schengen Agreement establishes various figures such as police assistance, border surveillance, hot pursuit, and controlled deliveries, which are very complex to apply at the Gibraltar Frontier, if not impossible.

Another well-known point of contention is the possible presence of Spanish police officers at the port and airport of Gibraltar if the announced removal of the Verja takes place after Brexit. This would require reaching an agreement for the extension of Schengen. It is one of the measures included in the European Commission's "comprehensive proposal" to reach an agreement with the United Kingdom. The European Commission and Spain propose that Frontex collaborate for an initial period of four years, but they consider it essential to have Spanish agents, as explained by Spanish Foreign Minister José Manuel Albares.

However, the United Kingdom and Gibraltar do not want uniformed Spanish police officers to control the two access points to the Rock by sea and air because they view it as a step back in the sovereignty of the Rock, which Spain claims. The latest solution proposed is for the agents to be present but in a less visible location and behind dark glass.

Gibraltar is not part of the United Kingdom's territory as a separate state. London considers it a British Overseas Territory and, as such, is responsible for its foreign relations and defence. The rest of Gibraltar's governance is based on an internal system of organisation with a certain degree of autonomy, as outlined in the 2006 Gibraltar Constitution. Among these areas is its judicial system, which is crucial in the new security system if the Verja were to fall. The United Nations and the Spanish Government consider Gibraltar a non-self-governing territory pending decolonisation.

For the control of people and goods—the gateway between the Schengen Area and Gibraltar—to be located at the port and airport, both parties must first reach an agreement that guarantees fair competition (a level playing field) in both territories. In other words, Gibraltar must adhere to European Union standards in areas such as state aid, employment, the environment, fiscal matters, combating money laundering, and countering terrorist financing. Additionally, it should ensure that the Port of Gibraltar competes fairly with other European ports, "particularly the Port of Algeciras," including bunkering services, among others. Above all, the EU demands that Gibraltar implement relevant provisions of European legislation regarding goods, such as the customs code, tax-related regulations (including VAT), administrative cooperation, and standards required for products in the Single Market. Provisions related to information exchange to prevent drug trafficking, smuggling, and tax fraud are also foreseen.

The European Commission proposes ensuring the application of a tax system in Gibraltar aligned with that of Spain, thereby minimising price differentials, particularly for alcohol, fuels, and tobacco products, with the aim of preventing trade diversion and smuggling.