British armed forces would be unable to reclaim the Falkland Islands if they were seized by Argentina, the former head of the Army has said.
General Sir Mike Jackson believes the demise of jets capable of launching from aircraft carriers would make it "just about impossible" to recover key strategic strongholds.
In an interview with The Sunday Telegraph, Sir Mike said British defences on the Falklands have improved "by a factor of several tens" since 1982.
But the 67-year-old conceded losing the islands - which Argentina calls the Malvinas - is not out of the question, saying, "never say never".
He told the newspaper: "The official answer will be that it would not be possible for the Argentinians to gain a foothold on the islands, in particular to take Mount Pleasant airfield, which is key to the British defence plan.
"We have a large international-sized airfield to allow for very rapid reinforcement by air, should circumstances so require. But I suppose I have learned in life, never say never.
"What if an Argentinian force was able to secure the airfield? Then our ability to recover the islands now would be just about impossible.
"We are not in a position to take air power by sea since the demise of the Harrier force."
Tensions have been mounting between Argentina and the UK following months of escalating rhetoric.
Buenos Aires reacted angrily in 2010 when Britain allowed offshore drilling for oil in the islands' waters, and the Argentinians were also irritated by the recent announcement of Prince William's forthcoming RAF posting to the islands.
The latest volley of comments has seen the South American country's president Cristina Fernandez hitting back at David Cameron, who accused Argentina of colonialism.
She said: "When they say these things it's exactly because they don't have reasons or arguments."
Asked about job cuts in the armed forces, Sir Mike said the fewer numbers were not too much of a problem as long as the UK is not engaged in a one-on-one battle with another country.
"This will be the smallest Army since the Napoleonic wars, he said. "My understanding is that we're heading for 82,000.
"Right now there is no existential threat to the UK. It's very hard to see when we would be involved in state-on-state warfare which threatens the existence of this country.
"If that were to happen, there would be time to move back to where we used to be."