Potentially a great deal — if it can be finalized. Gibraltar’s economy is based on services including banking, insurance and online gambling to the U.K. and other countries. Half of the territory’s working population of 30,000 crosses the border daily, including about 10,000 Spanish commuters. Their salaries, plus the business of supplying Gibraltar, are a lifeline for Spanish towns close to the border, where the unemployment rate is much higher than the nation’s average. High unemployment is already one reason why Linea de la Concepcion, the closest town to the border, is known as a gateway for illegal drugs entering the EU.