At the time, the White House blamed the loss on a technical problem causing a loss of control. Iran claimed to have brought the drone down by electronically disrupting its GPS system.

US military officials tried to play the incident down, saying Iran did not have the technology to decipher the drone’s secrets, and President Barack Obama asked the Islamic republic to return the Sentinel.

Joe Lieberman, then chairman of the Senate homeland security committee, said: “It was not good for the US when the drone went down in Iran, and not good when the Iranians grabbed it. [But] I don’t have confidence at this point that they are really able to make a copy of it.”

“It’s a very sophisticated piece of machinery and has served our national security well, including, I would guess, being used to look all over Iran, particularly at areas where we have reason to believe that they are working on a nuclear weapon.”

In the footage broadcast on Sunday, an officer said: “Our engineers succeeded in breaking the drone’s secrets and copying them. It will soon take a test flight.”

Iran has been working to develop a drone programme. Some of its unmanned aircraft have a range of hundreds of miles and are armed with missiles.

The state broadcaster also showed images that the commentary said had been recorded by an Iranian drone above a US aircraft carrier in the Gulf. In the pictures, which were relatively clear, it was possible to see American personnel working on planes and helicopters aboard the vessel.

The broadcast showed supreme leader Ayatollah Ali Khamenei’s visit to an exhibition organised by the Revolutionary Guards air wing about Iran’s military advances, particularly regarding ballistic missiles and drones. Footage showed two nearly identical craft.

“This drone is very important for reconnaissance missions,” Khamenei said, standing in front of the Iranian copy of the American aircraft.

11 May 2014