The Hercule Poirot-like figure of Major Anthony du Gard Pasley stepping from the gangway of Swan Hellenic's Minerva II was a sight to behold. Immaculately dressed in plus fours,curled moustache, cravat, monocle and thumbstick, you would never have guessed that he was nudging 80. He could've been dressed for a pheasant shoot on his estate in Dumfriesshire, but no, this was the bus trip to the ancient city of Leptis Magna, an hour and a half away from Tripoli. Along with several hundred of his fellow passengers, many quite a bit older, but just as intrepid (the average age on the ship was 69), he obediently filed on to one of the waiting buses.

Half a century ago, in what some would call the heyday of Swan Hellenic Cruising, you could be forgiven for thinking that you had joined an old fashioned London club and put to sea. Everyone seemed to know each other, and what few strangers there were would soon be exchanging names and addresses, vowing to meet up on a future voyage.

The men behind this particular style of discovery cruising was WK Swan and his son Ken, who died two years ago at the ripe old age of 86. Together they ran Swan's Travel Bureau, which brought them to pioneer a particular style of cruising that goes back to 1951, when the Swans were approached by the University of London Hellenic Society to arrange a tour to Greece for its members.

That first cruise cost 80 guineas and took 268 passengers from Venice to Istanbul, Troy, Ephesus, Athens, Delphi and six Greek islands. On board, guest speakers included Sir Mortimer Wheeler, the eminent Scottish archaeologist, and from this developed a style of cruising that Swan Hellenic was justly proud of. The specialist guest speakers gave daily lectures and took an active part in guiding their mostly British passengers around a fascinating range of historical sites.

A glance down the passenger list of one of those odysseys would have revealed names like Harold Macmillan, Joyce Grenfell, Celia Johnson and Frankie Howerd - all eager to lap up the close and personal approach that Swans offered.

From 1996 until 2003, a much smaller ship, also called Minerva, became the mainstay of Swan's operations. She sailed with about 300 mature passengers, accompanied by such top-class speakers as Sir Roy Strong and Professor Barry Cunliffe. That too was a golden period. The news that Swan Hellenic was to replace her with something much bigger - a modern, high-rise vessel - came as something of a shock.

There was a lot of affection for the old ship, which was then owned by P&O; and despite being named Minerva II, it didn't stop the whispers of doubt spreading through the die-hard Swans (you traditionally become a Swan after your first cruise), who in some cases had done 50 or more cruises.

To begin with,they were suspicious of Swan Hellenic's new owners, the giant Carnival Corporation, which had swallowed up P&O. Would it, they feared, mean a steady dilution of what they had come to know and love - namely a close-knit party of like-minded cruisers setting off to view the world's historic sites in comfortable surroundings, enjoying good conversation with fellow passengers and tasteful entertainment after dinner?

Certainly Minerva II is more than twice the size of anything they had sailed on before. It caters for 700 passengers (although Swans have said they won't go over 600), has very smart cabins with balconies, an outside lido deck with swimming pool and sunbathing space, jogging track, a therapy pool, gym, and golf driving net. The public rooms are elegant too. There is a spectacular observation lounge with fantastic views through floor to ceiling windows. There are several bars and four restaurants, ranging from a formal dining room to the Bridge Café, all with open seating.

Yet a 600 passenger ship is far from large by today's standards of cruising. While the new ship is much bigger, she's also a lot more comfortable than the old one. As for the camaraderie, it's still there, but you have to search for it. The British captain, Mark Dexter, was most welcoming, and all the staff we met on board worked extremely hard at making the cruise as seamless as possible.

There's a modern, sumptuous spa, run by Sonya from Sydney, who's on hand to soothe any aches and pains from elderly bones; while the lecture programme expertly covers subjects like archaeology, anthropology, zoology and wildlife.

On board entertainment revolves around classical concerts and choral music, jazz and drama. There is a library of 4000 books, with plenty of space to sit and read. Certainly there's no question of it not hitting its much deserved four-star rating in the Berlitz Guide to Ocean Cruising, the bible of the cruising world.

We snuggled down in the evenings to enjoy a group called Absolutely Opera sing Gilbert and Sullivan on our cruise out of Athens, which took us to North Africa, southern Spain and on to Madeira and the Canaries. The Leptis Magna trip was a highlight.

It's a Roman city of incredible size, and yet only 10% of it has been excavated. There is a basilica, a forum and the arch of Septimus Severus, the locally born Roman governor under whose rule the city reached such dizzying heights of prosperity. Fantastic, Hadrianic baths with marble statues and floors and fine mosaics were everyday décor here.

We got tired of the local guide, so we sneaked off and ate our picnic on top of the amphitheatre which looks out over the city; and let our eye run down the Roman roads to the harbour, rather than our tired feet. It was a thrilling visit, but it would have been even more special if Sir Alan Munro, one of the three lecturers on board, could have given us some ins and outs of Leptis. Sadly, that was impossible, for there were just too many of us, and we were in the hands of the local guides and their rather deadpan accounts.

The decision by Swan Hellenic to go for a bigger and swankier ship must have had a lot to do with the demand for their cruises. According to Victoria Kennedy, a management bigwig who spends a lot of time at sea, their cruises are mostly full. "A bigger ship means we can offer more entertainment and more choice, and we are always interested in widening our destinations and inviting new lecturers on board," she told us.

A vox pop conducted with the passengers brought a mixed response as to whether going for this larger ship meant Swan Hellenic had lost sight of its priceless, 50 year history and the Swan concept of personalised, tailor-made cruising.

Over lunch with the Major, he confessed in a whisper that he thought it had, but it wouldn't stop him sailing again. In fact he had already signed up for another.