Luton airport in Bedfordshire has been evacuated following a security alert, disrupting air travel for thousands of passengers.
A bomb disposal team was called and a controlled explosion was carried out. Bedfordshire police later confirmed it was "not a home-made bomb" after speculation on some websites.
Pictures posted on Twitter showed travellers massed outside the terminal at Luton airport.
A spokeswoman for the airport said: "London Luton Airport has evacuated the terminal building after a suspicious item was found in the security search area.
"The decision has been taken with the police to ensure the safety and security of passengers and staff. Further updates regarding the security and operations at the airport will be provided as soon as possible."
The airport said some flights are departing where passengers had already cleared security search.
Bedfordshire Police were contacted by concerned airport staff just after 1.30pm.
The main terminal building was immediately evacuated and the bomb squad are now examining the package.
The airport is close to junction 10 of the M1 motorway and the emergency has meant traffic chaos in and around the airport.
The evacuation has not affected Luton Airport Parkway railway station, where trains are currently running normally.
"The decision was taken to close the airport to ensure the safety of passengers and staff. The Explosive Ordnance Disposal team have arrived at the scene to identify the item."
Luton said later that all incoming flights had been suspended and the approach road to the airport had been closed.
An airport spokeswoman added: "Passengers are advised to contact their airlines to establish the status of their flights."
At least nine flights have been diverted to Stansted airport in Essex.
Ryanair issued a short statement:
"Luton Airport is currently closed. Two Ryanair aircraft have diverted to London Stansted Airport and will return to Luton when it reopens"