Iberia is suspending its flights between Madrid and Gibraltar at the end of the week for economic reasons, the Spanish airline says.
It will leave the British territory without any air links to Spain.
“The last flight will be on September 28,” a spokeswoman for the Spanish flag carrier said.
Spain, which claims the rocky outcrop off its southern coast, allowed regularly scheduled flights in December 2006.
It followed a political meeting between Britain, Spain and Gibraltar under the tripartite forum, which seeks to establish areas of cooperation between the territory and Madrid.
Iberia started daily flights on December 16, 2006. This was followed by British Airways in May 2007.
But BA withdrew from the route in September that year due to what it said were operating restictions at both airports.
The Spanish airline has now said it is suspending the route for commercial reasons due to insufficient demand for its reduced schedule of twice-weekly flights.
“Iberia continually reviews the viability of the destinations in its network and it has now decided to halt this route,” the spokeswoman said.
The decision will be a blow to the tripartite talks, as the resumption of the air link between Gibraltar and Spain was seen as a visible symbol of the success of the talks.
The Gibraltar government is lumbered with the building of a new, enlarged air terminal at a cost of £48m.
The only air links remaining are with British airports, serviced by British airlines.