By Dominic Casciani
BBC News Online at the National Archives
Britain's top civil servant suggested an anti-terrorist force of Securicor guards for the QE2 might be better than the SAS.
QE2: Fears it had become target
Whitehall was split over how to handle a 1973 cruise to Israel by the vessel.
It feared the liner would be a target in the fall out of the terrorism attack on the 1972 Munich Olympics.
No threat emerged - but rumours persist to this day that Egypt's President Anwar Sadat prevented the ship being treated as a target by militants.
According to the documents released to the National Archives, Cunard asked the Ministry of Defence to supply an elite anti-terrorism unit for the ship's planned cruise celebrating the 25th anniversary of the founding of Israel.
The majority of the passengers were expected to be wealthy Jewish-American clients.
But the company feared the ship, regarded as the most luxurious in the world, would become a target for Palestinian of Arab militants on its cruise through the Mediterranean.
Those fears may not have been unfounded.
In 1972, the SAS and bomb disposal officers had been scrambled to the ship, then 1,000 miles from land, in response to a bomb threat and ransom demand.
The threat turned out to be hoax and the FBI caught the culprit. But the soldiers had risked their lives by parachuting into the Atlantic next to the ship and were honoured by the Queen on their return.
Sir Burke Trend, the Cabinet Secretary, warned Prime Minister Sir Edward Heath that the QE2 had probably become a "particularly vulnerable and tempting target".
But he added: "If we allow the terrorists to compel us to cancel this cruise, where will they bring pressure to bear next?"
The biggest problem appeared to be whether or not a British soldier stationed onboard could open fire on an enemy.
Legal opinion suggested they could not, because the ship was a private vessel and soldiers could face murder charges if they acted in another country's territorial waters.
The Foreign Office thought most of this absurd.
"If ministers decide there is to be an armed force on board, the members of such a force could hardly be expected to sit still and do nothing in the event of a terrorist attack merely because the attack took place in, or just outside a foreign port," said one civil servant.
Israel said it was willing to provide an anti-terrorism unit. That offer was immediately - but politely - declined as Whitehall concluded its troops would act as a spur to potential terrorists.
Sir Burke thought he had the answer.
SAS: Elite anti-terrorism training
"We could suggest to Cunard that they try to raise a force of their own or seek help from an organisation such as Securicor," he suggested in one memo.
He then checked himself and conceded the company's employees would be probably "quite unfit" for the task. The Prime Minister's response is not recorded.
However, the firm did eventually appear in the plans as one of two private security contractors providing visible security at port.
For its part, the Ministry of Defence, decided on a force of some 26 elite commandos.
The ministry did not have to look far for volunteers - the majority would be travelling incognito as passengers, sipping pina coladas on the sun deck.
Others would be stationed on the bridge to guard the captain while Navy frogmen would guard against underwater attack.
By this point, details had begun to leak and national newspapers scrambled to get reporters on board.
Archives show they made the most of the trip, filing dramatic stories of security risks amid the caviar.
At which point another ministry declared an interest in the proceedings.
"I have no objection to our helping Cunard with the security arrangements," wrote Patrick Jenkin, Chief Secretary to the Treasury.
"But these should be provided on the same terms as security services provided by commercial firms; full repayment charges should be agreed in advance."