A United Airlines Boeing 767 has just declared an emergency right after departure from London Heathrow Airport.
The United Airlines flight #UA147 departed London Heathrow Airport on time, at 15:10 GMT, 50 minutes ago.
The Boeing 767-300ER (registration N665UA) took off from runway 27R and stopped the climb at only 18,000ft before performing a turn around.
UPDATE 16:05 GMT
The flight descended to 13,000ft, turned around.
UPDATE 16:24 GMT
We have confirmation flight #UA147 is returning to London Heathrow due to a technical issue.
UPDATE 16:37 GMT
The Boeing 767 has landed on runway 27R.

UPDATE 16:39 GMT
The plane was surrounded by emergency vehicles on taxiway.
UPDATE 17:10 GMT
The plane is out of service to address a technical issue, after it experienced an engine issue. The flight is now cancelled.