A spokesman for easyJet said the plane made an emergency landing as a result of the Captain "requiring medical assistance".
He said: "The First Officer performed a routine landing in line with procedures.
"The aircraft landed safely and was met by emergency services on arrival.
"The safety and well-being of its passengers and crew is easyJet’s highest priority."
He continued: “easyJet sent a replacement aircraft and crew from London Gatwick to Venice to operate the flight to Heraklion. This flight has now arrived into Heraklion.
“We apologise for any inconvenience experienced due to the diversion and resulting delay.”
The drama comes after the captain of an American Airlines plane died while flying from Phoenix to Boston.
