Ryanair flight FR25, with six crew and 172 passengers on board, including 71 schoolchildren from St Leo's College in Carlow, took off on schedule at 1.20pm local time, beginning what should have been a routine 80 minute flight to Dublin.

However, what transpired over the following 12 hours was anything but routine. Within an hour of the plane taking off, a note was handed to a crew member by one of the passengers. By the reaction on the crew member's face, it was clear to those watching that something was up. The note, written on a Ryanair brochure, contained a chilling message: there was a bomb was on board the aircraft.

Most passengers were blissfully unaware that anything was wrong at this point. Retired journalist Charlie Fitzgerald, who was sitting in the second row of seats, said the first he noticed out of the norm was that the 'fasten seat belts' sign had been on for a long period - as normal when the plane begins its descent flying over Liverpool - but there was no sign of the cabin crew being asked to take their seats. "We're going nowhere fast, " he said, joking with a fellow passenger.

A diversion to safety But the plane was going somewhere; it was heading to Prestwick Airport on the west coast of Scotland, some 30km from Glasgow. Passengers were told by the pilot that the plane was diverting to Prestwick for "operational reasons".

Unknown to passengers, there was a flurry of communications going on between the cockpit, the RAF, the British Ministry of Defence and Department of Transport, Air Traffic Control and Strathclyde Police. At 1.45pm Irish time, an RAF Tornado F3 was diverted from a routine training flight to escort flight FR25. A further two Tornados were also scrambled from RAF Coningsby.

Passengers reacted with amazement when they looked out their windows and could see the three Tornados. It was clear that the problem was more than just "operational". The pilot, presumably conscious of passengers' growing concerns, came back on the intercom to tell passengers that there was talk of a bomb on board but adding that he was sure it was just a joke. His calm demeanour skilfully headed off any potential panic. "We knew he wasn't worried. He smoothed everything. He was brilliant. The chief steward was also very unconcerned looking, " recalls Fitzgerald.

However, nerves were understandably frayed. Passengers describe as "really scary" the thirty minutes between the announcement and the plane touching down in Scotland at 2.22pm. Prestwick is one of two UK airports used for such emergency situations - chosen because of its large runway and the absence of a major urban conurbation in the immediate vicinity. A 25-mile air exclusion zone was set up around Prestwick, delaying all flight operations there and at nearby Glasgow Airport.

If passengers thought that their frightening ordeal was about to end on touchdown, they would be mistaken. The plane and its occupants were left in the middle of an isolated runway. About a quarter of a mile away were the fire services. Despite the bomb threat, the doors remained closed. Repeated requests by the pilot - who has statutory responsibility for the safety of the plane's occupants - to disembark the passengers, and for coaches to be sent to pick them up, were denied by the authorities.

Instead, passengers in the back row were asked to go to the front of the plane, while two cabin crew members - without any expertise in the area of bomb disposal - searched the seats and overhead lockers. When this was done, the passengers returned to their seats and the process was repeated for the next row of seats.

This method of searching was extremely time consuming and a number of passengers became upset and were in tears. At 3.30pm, the pilot was able to communicate that passengers would be able to disembark in 15 minutes, but then it emerged that a meeting was taking place in the airport to decide what to do. At 4.45pm - 20 minutes after Prestwick Airport was reopened - two sets of steps were pushed up towards the plane but left tantalisingly five or six feet away. By this point, only around half of the plane had been searched, but at least refreshments were being served from the bar by the cabin crew.

Ten minutes later, the steps were put in place and the doors opened - over two-and-a-half hours after the plane had landed. Uniformed police boarded the plane and passengers were told to disembark with their passports, but without their baggage. They were boarded on buses and taken, under police escort, to a secure part of the airport. At the top of a long corridor was a reception area where immigration officials were waiting. Passengers were brought up 20 at a time to be cleared.

The stressful conditions had taken their toll on a number of passengers, including Charlie Fitzgerald, who has a heart condition. He was treated by ambulance crew, who found that his blood pressure was extremely high, and later by a doctor who gave him medication and told him his condition was very serious. "I was bloody worried about my health, " he said this weekend. He recalled that an elderly French couple thanked him for making a fuss, because the French man also had a heart condition.

Once through immigration, the passengers were brought to an isolated room. Volunteers from the South Ayrshire County Council were on hand to provide tea and sandwiches; "they were marvellous", says Fitzgerald. Each passenger had a number stamped on their left hand and each was given a card to hold up in their right, while they were photographed by a police photographer. Fitzgerald claims that when he challenged a police officer over their right to take their photograph, the response was "we have the power to do anything".

End of the ordeal After tea and sandwiches, each passenger was interviewed by two police officers for an average of 15 minutes.

While this was going on, the plane was being searched by a military bomb disposal unit, which didn't find anything suspect. By 9.45pm, Strathclyde police had released the aircraft and completed all passenger interviews. An hour later, the rescheduled flight left Prestwick, finally landing in Dublin Airport at 11.30pm, almost 10 hours after the exhausted and emotionally drained passengers and crew had expected to arrive.

While passengers were high in their praise for the pilot and the cabin crew, a number of them complained that there was nobody from Ryanair to meet them on their return into Dublin. But the real questions will be directed at the UK authorities and, especially, Strathclyde Police, for the decision to keep the passengers on the plane, with a suspected bomb, for over two-and-a-half hours.

David Learmont of the respected industry magazine Flight International has described the operation as a "monumental cock-up" and questioned whether any procedures were in place.

In a statement, Strathclyde Police said it had carried out a "full risk assessment" and "at all times, the safety and well being of the passengers was a priority", adding that if any time an assessment was made that the passengers were in any danger, they would have been "immediately evacuated from the aircraft".

But the statement raises more questions than answers, most notably: what was the rationale for keeping passengers on board the plane and why was it left to the cabin crew rather than trained bomb disposal experts to search the plane for a bomb? Charlie Fitzgerald summed it up neatly when he said that if there was a bomb on board, passengers were being left "like Easter lambs for the slaughter" and if there was no bomb, why were they left on the plane for so long?

PA Delayed Aer Arann flight reaches Galway

THE Aer Arann flight, diverted to Glasgow Prestwick late on Friday night after a bomb scare, flew into Galway Airport yesterday afternoon after being cleared by Strathclyde Police to continue its journey.

The flight from Luton Airport to Galway had to divert to the Scottish airport after staff found a note claiming there was a bomb on board. The plane was escorted to Prestwick by two RAF Tornado jets and landed just before 11pm.

A Strathclyde police statement said the four crew members and 49 passengers were "evacuated as a priority". This is in contrast to last Wednesday's Ryanair flight, diverted to Prestwick in similar circumstances, when passengers were left on board for over twoand-a-half hours.

The Aer Arann plane's occupants were interviewed by police and a full search of the plane revealed "nothing of note", police said. Passengers were accommodated in a hotel overnight before continuing their journey to Galway yesterday.