A Boeing 777 bound from Cairo to New York with over 300 passengers on board has been forced to land at Prestwick Airport after an apparent bomb threat.

The incident was sparked after a passenger found a note in a plane toilet, on which was written: "I set this plane on fire".

Air traffic control at the airport confirmed that Egyptair flight 985 to JFK had been diverted and touched down at 2.30pm.

The Ministry of Defence confirmed it had been escorted into land by Typhoons from RAF Leuchars.

The BBC said one of its New York producers, Nada Tawfik, had found the note.

She told the BBC News Channel this afternoon: "I'm still on board, we were told that we would be able to get off half an hour ago but we're still here on the plane and as you can imagine it's a pretty tense situation.

"Everyone is out of their seats and everyone is very concerned and we don't have much information at all.

"I'm actually the one who found the note in the rest room. When I went in to change my daughter about three hours into the flight, I found a note by the sink saying 'I set this plane on fire' with the seat number 46 D written on it.

"So I immediately went to the crew and told them about it.

"It was on a hand napkin written in pencil and the pencil was actually still there so I told the crew to make sure to keep it so they can get any finger prints off of it. They locked the bathroom immediately so that no one could go into it.

"It almost looked like a child's handwriting or someone who has very sloppy handwriting, but it was very alarming especially these days when everyone is so concerned about safety on flights. I said to one of the stewardesses 'I don't know if this is a prank', they said no, it can't be a prank.

"Either someone has a very bad sense of humour or, you know, it's very scary.

"No security has boarded the plane we're all just waiting to get off, people are out of their seats, It's a bit chaotic, no one really knows what's going on."

Police confirmed a suspicious note was found on the plane and all passengers are to be interviewed.

A spokeswoman said: "At around 1420 hours today an Egyptair aircraft flying from Cairo to New York was diverted to Prestwick Airport after a suspicious note was discovered on the aircraft.

"There are no reports of anyone injured and police are currently making arrangements for the 326 passengers to disembark.

"All passengers will then be interviewed by police."

Scottish emergency authorities staged a full-scale response. One driver reported seeing five police cars, fire engines, and ambulances travelling southbound on the A77, apparently heading for the airport.

At least one police vehicle was later seen on the runway near the plane.

Train and bus services between Glasgow and Prestwick have been suspended meantime.

Transport in the area has been further disrupted as officers closed roads near the airport.

Tawfiq Assi, chairman of EgyptAir, said flight 985 had 326 passengers onboard when it was diverted to Prestwick.

Mr Assi said the flight was now being checked by a technical team that includes bomb disposal experts.

The passengers were let off to wait in the airport, but officials are also looking into their backgrounds. They are expected to be interviewed by police.

A Prestwick Airport spokesman said he could not discuss the nature of the incident.

"The (diverted) plane was on route from Cairo to JFK in New York.  It is safely on the tarmac at Prestwick.

"The airport is open for business with flights arriving and taking off.

"The police are involved and on the scene, they have the lead in this."

The Boeing 777 is the world's largest twin jet with seating capacity for 300-400 passengers.