A Greek passenger plane is being searched at the UK's Stansted Airport after being diverted by a bomb alert.
The plane being searched at Stansted
Olympic Airlines flight 411 was en route from Athens to New York when a Greek newspaper took anonymous phone calls saying there was a bomb on board.
UK RAF jets were scrambled and escorted the plane, with 301 passengers and crew, to Stansted, in Essex, on Sunday.
Police said it was not a terrorist attack or hostage situation and nothing suspicious had been found on the plane.
Essex Police said "well-rehearsed procedures" had immediately been followed once the alert happened.
Assistant Chief Constable Liam Brigginshaw said officers were working methodically to check a "substantial amount" of hold baggage and five
tons of cargo which the plane was carrying.
"We are working with sensible procedures to ensure the safety of passengers, the aircraft and the airport, which is still running with no disruption to its operation."
A spokesman for Stansted Airport said the plane had landed at 1529 BST under "full emergency conditions" and the situation had been handled "extremely well".
Since the September 11 attacks, it has been normal procedure for threatened planes to be accompanied into Stansted, the UK's designated hijack airport, by RAF
The BBC's Athens correspondent Richard Galpin said the incident happened after three anonymous calls were made to the Greek newspaper Ethnos, in Athens.
According to a tape Ethnos made available to journalists, the first caller said: "Flight 411 Olympic for America has a bomb for Iraq."
In a second call, a voice that sounded like a different person said: "Are you listening? Flight 411 Olympic for America, bomb. America will see. Six o'clock message for you."
The first is believed to have been made by an elderly man speaking in broken Greek two and a half hours into the flight.
Three further calls - at least one by a person who spoke more fluent Greek - were received within the next hour and a quarter.
The paper contacted the police, who called the airline. No code word is believed to have been used.
A spokesman for the UK's Department for Transport said the aircraft "is on the ground and being searched as part of a standard response".
"Fortunately nothing has exploded, if indeed there was a bomb on board, but we take all threats seriously."
The RAF is not releasing any more details of how many of its planes were involved for security reasons.
It is believed that RAF Tornados escorted the planes
A Ministry of Defence spokesman said the pilot had contacted air traffic controllers for help.
Officials called the Department of Transport and then the MoD gave the go-ahead to escort the plane.
Leonard Vlamis, chief executive of Olympic Airlines, said: "We were told to land at Stansted which it did safely. The passengers are all okay.
"The passengers were calm and they were evacuated properly and safely. There was no problem inside the flight - everything was normal."
He said they had outlined their "strict" security measures to the authorities, which included screening all passengers and baggage and checking the aircraft by police and sniffer dogs.
The Olympic Airlines jet is being kept in a secure holding area away from the main airport building.