A British Airways jumbo jet flying over U.S. airspace was forced to return to Heathrow after a major terror scare, it has emerged today.

The Boeing 747, which was bound for Mexico City, was more than halfway across the Atlantic last Friday when U.S. authorities barred it from entry into its airspace due to “serious concerns” about one of its passengers.

Flight 243 was ordered back to Heathrow more than two hours into the flight when authorities spotted a “data discrepancy” with the 55-year-old American man.

A BA spokesman said: “The BA243 Heathrow to Mexico City flight returned to Heathrow on Friday afternoon due to a data discrepancy with a US citizen.”

“The aircraft returned to Heathrow and a passenger was asked to leave the aircraft, which he duly did and collected his bags.

“We apologise to the 317 other passengers onboard the Boeing 747 for the inconvenience caused. The aircraft had more fuel loaded at Heathrow and took off for Mexico again on Friday evening as normal without any further issues.”

A Department for Transport spokeswoman said: “There has been no breach of security at Heathrow as a result of this incident.”

The American was escorted off and searched under antiterror laws. But Scotland Yard said the man had not been arrested.

It is believed to be the first time since 9/11 that a British plane has been barred from US air space.

The mid-air drama follows the arrest of Nigerian Al-Qaeda suspect Umar Farouk Abdulmutallab who is accused of trying to blow up a plane bound for Detroit on Christmas Day.

The foiled attack was followed by a heightening of global security including the introduction of controversial full body scans at airports.