It is believed that the reason for the diversion of Kuwait Airways Flight 118 was a medical emergency and not a terrorist incident.
The plane sent out an emergency signal as it travelled over Europe shortly after 8 am (local time) and turned back over Germany.
The Boeing 777 headed straight for Britain and landed at the Heathrow Airport.
A Scotland Yard spokesperson said: "It was a routine diversion for a medical emergency."
Media reports suggested the landing was forced due to an outbreak of food poisoning on board. Unconfirmed reports are claiming that at least six passengers were being affected by severe food poisoning.
The flight is expected to continue its journey to Kuwait City later today.
The event came a day after a suicide bomber blew himself up during prayers at a Shia mosque in the Kuwaiti capital, killing 27 people.
