It was supposed to be the voyage of a lifetime.

In 1973, to mark the 25th anniversary of the state of Israel, the Cunard shipping line arranged a special Passover Mediterranean cruise to Haifa, on the QE2 — the company’s flagship.

With passengers able to celebrate the Sedarim in style aboard the world-famous liner, travelling to Israel, it would bring a new meaning to the phrase “next year in Jerusalem”.

And then all hell broke loose.

Shirley Kempner, now 91, was supposed to go on the trip.

“My husband Sidney and I were dentists, and at the time he was the chief dentist for Gillette,” she recalled.

“The doctor in the company’s medical department worked part-time for Cunard. He said to my husband: ‘The dental officer on the QE2 doesn’t particularly want to do this trip, would you like to be the locum and go instead?’

“My husband loved the sea, so he thought ‘marvellous - the trip of a lifetime’. Our three children were young, and we were offered a place on the ship – we could go as passengers. I thought it was fantastic.”

But then, talk of a possible terror attack began, thanks to Libyan leader Colonel Gaddafi.

“He decided he was not going to allow this – he was going to blow up the QE2 on the way,” Mrs Kempner said. “He made this public and said it’s not going to get there, it’s going to be blown up with everybody on it.

“Well, the QE2 was a great British institution. They asked the head of Cunard whether he would cancel the trip. He said no.

“It all had to be staffed. They koshered everything for Pesach, there was a kosher kitchen, all the cutlery was changed, the lot.”

The ship’s security was massively increased. According to a newspaper report from the time, “when the liner leaves on Sunday, a party of armed Royal Marines will be on board, and during the liner’s passage through the Mediterranean on the way to Ashdod and Haifa she will be escorted by a guided missile ship of the Royal Navy and by Nimrod aircraft.”

According to reports published the following year, Anwar Sadat, then the president of Egypt, claimed he had intervened to stop the Libyan leader torpedoing the liner.

Mr Kempner joined the ship on the Friday before it was due to sail, with Shirley and the children heading to Southampton on the Saturday night. They received an unwelcome surprise.

“We met my husband there”, Mrs Kempner said. “With a very long face, he said ‘I can’t let you go. They’re sending divers down to see that there are no limpet mines around the ship. They’re going to have an escort of light planes and helicopters all the way out. I have a station to cover in an emergency. If I know that you’re all in different places, I will feel dreadful.’

“So we had a lot of tears but we thought in the end that would probably be the best thing. So me and the kids had to turn around and go home, because it was Seder night the next night.”

Thanks to some family members, Mrs Kempner and the children were invited to a Seder, and managed to get hold of some Passover products at short notice. But she was determined to join her husband – after her first plan (to fly out to Lisbon, where the ship was to stop) failed, she managed to fly to Israel, meeting the ship in Ashdod and sailing with her husband - who died several years ago - for the last leg of the voyage, to Haifa.

It was clear it had not been an ordinary trip. Staff had been offered an extra £50 – then a considerable sum – in danger money for serving on the cruise.

“A lot of the crew wouldn’t go. They were afraid. I can’t blame them, in a way. My husband said that there weren’t a lot of passengers on there, for the size of the QE2 – an awful lot had cancelled. He said that most of the people he saw were security, secret service people.

“He tried to talk to them and they were a bit tight-lipped – wouldn’t say very much. But he saw one of them had a newspaper sticking out of his pocket which was in Arabic. He said ‘I see you speak Arabic’. So this chap covered it over and said: ‘We’ve got to be equipped for everything’. Didn’t say he was secret service.”

Events overtook the story of the cruise – just months later, Israel found itself in a struggle for its survival during the Yom Kippur war.

A year later, in response to President Sadat’s claims, Victor Matthews, the (Jewish) chairman of Cunard, had a letter published in the national press, in which he said: “With the precautions that were taken, the chance of a successful attack by the type of submarine in question [President Sadat had referred to an ex-Russian Romeo class submarine] is virtually nil.”

However, in the same letter Mr Matthews confirmed that “the ship was under orders to complete the final day’s voyage to Israel at her maximum speed of something over 30 knots, to extinguish external lights as far as was practicable, and to vary her course in zig zag fashion if warned of any possible hostile presence.”

The process was described as being similar to that done by Cunard liners while acting as troop ships during World War Two, to avoid U-boats.

Although the shipping line would never again offer a similar voyage on subsequent Israeli anniversaries, the story ended well, at least, for one crew member.

“After that they asked Sydney if he’d be the QE2’s locum every time the dentist went on holiday,” Mrs Kempner said.

“He loved that.”