The BAE 146 RAF passenger jet experienced a fault with the aircraft’s hydraulics on Sunday afternoon on a flight from London to Brussels.
All flights in and out of the airport were suspended while emergency crews dealt with the emergency.
A Foreign Office spokesman told The Guardian: “There was a technical issue on the RAF flight on Sunday afternoon carrying the foreign secretary and his officials from London to Brussels that required the aircraft to land at Luton airport.
“The foreign secretary thanked the RAF crew for their professionalism and was grateful to Luton airport for the brief, unscheduled welcome. After a short delay, the foreign secretary continued on his way to Brussels by alternative means.”
It’s been a rough first few days for Johnson in his new role as Foreign Secretary.