Cruises are big business. So just what does it take for a tour operator to put together a profitable voyage around the Greek islands?

On the quayside in Corfu, she was dwarfed by the intimidating bulk, in the adjacent dock, of an Italian cruise ship – the MSC Musica, doing a good impression of a Milanese apartment block. Yet even though the Thomson Spirit was a mere slip of a ship, for us passengers newly arrived from Luton, Newcastle or any of a dozen other UK airports – plus a few guests from Dublin and Helsinki – she was a welcome sight.

Our home for the following week would drift around the Aegean, providing half-a-dozen different destinations while allowing us to unpack our suitcases only once. And the sight of 1,250 merry passengers climbing the gangway to Deck 2 must have gladdened the heart of any shareholders in Thomson's German owner, Tui (formerly, implausibly, Preussag – the Prussian Mine and Foundry Company).

While the total amount that the passengers paid for this "Pearls of the Aegean" cruise is a closely guarded commercial secret, making an educated guess is straightforward. I paid £707, including a flight from Luton and back. But that was for the cheapest cabin type (number 522). While other people spent less – a couple who booked five days before departure and flew from East Midlands boasted of paying only £555 per person – plenty had paid considerably more, for example for the privilege of a porthole. It is reasonable to conclude that the average price was no less than £800, earning Thomson £1m.

Most of that million was handed straight on to everyone involved in the extraordinarily complex choreography of a fly-cruise holiday: from the air-traffic controllers who guided our Boeings to Corfu, to the composers of the tunes that entertained us at night.

A week of Greek island hopping not only unlocks some of the secrets of the business of cruising, it also enables you to see some of the highlights of south-east Europe with none of that tricky backpacking palaver that characterised my first trip to Corfu and Crete 35 summers ago.

A large chunk of my "million-pound cruise" estimate goes to the airlines that bring the passengers around 1,500 miles from Britain to Corfu. Most people arrive on the in-house carrier, Thomson Airways, but it faces a skyful of costs, too.

George Osborne demands £11 for everyone aged two or over flying from a UK airport; the Chancellor earned around £13,000 from my cruise with no effort at all. And even a pair of lucky Luton taxi drivers claim a share of the million pounds.

The Norwich flights are operated as part of what is known in the trade as a "W" pattern. Thomson Airways does not have a base at the Norfolk airport. So the plane flies from Luton to Corfu early in the morning, then returns to Britain – but to Norwich. While it is in the air, a couple of taxis are taking fresh pilots and cabin crew from Luton to Norfolk. They meet the incoming aircraft, and fly it back to Corfu and eventually home to their base at Luton. Meanwhile the original flight crew jump into the taxis at Norwich and travel back to Luton.

The advantage of departing at an ungodly hour from Luton rather than spending six days hitch-hiking across Europe is that you reach the heavenly island of Corfu before it has slumped into a siesta beneath the warm, heavy blanket of the Ionian sun. The Venetian walls rise from the sea to wrap the old town in stone. The easiest way to appreciate the city is to imagine it as an Italian village, complete with indulgent cafés and hidden crannies – and augmented by curious Orthodox chapels, plus a cricket ground where military parades used to take place. And wandering through the gracefully peeling layers of history provides an ideal overture for a week of drifting indolently around the eastern Mediterranean.

Not many years after my first trip to Greece, the Thomson Spirit was born. Even by the standards of the budget end of the cruise industry, she has had a long and chequered history. She was built in Brittany in 1983, in the same St-Nazaire shipyards – Chantiers de l'Atlantique – as the Queen Mary 2. She began life as the Nieuw Amsterdam, part of the Holland-America Line. As she began to show her age relative to bigger, brasher and newer ships, she was sold off. She sailed to Sydney for the 2000 Olympics to act as a hotel ship, then joined a start-up cruise line in Hawaii as the M/S Patriot. Her owners went bust following 9/11, and she was moored morosely in Honolulu for a couple of years until the Holland-America Line bought her back.

You might imagine that as Europe's biggest holiday company, Tui would own its cruise ships. In fact, the Thomson Spirit is still owned by the Holland-America Line, which in turn is part of the giant Carnival Corporation – owner of Cunard and P&O Cruises, among many others, and effectively a competitor to Thomson. The tangle of interests gets even more complicated, because the Holland-America Line chartered her not to Thomson but to Louis Cruises, a Cypriot cruise line, which leases the ship and officers to Thomson.

The captain, Konstantinas Skourlis, is expert and charming in equal measure, as the role of master of a cruise ship demands. (His previous job was shuttling between Rosyth in Scotland and Zeebrugge in Belgium.) Captain Skourlis is Greek, as are the majority of his officers. The rest of the crew are predominantly Filipino, Goan and Eastern European.

On most cruise ships, a large proportion of the crew's earnings comes from tips (some US lines insist that passengers pay gratuities at specific levels, before the voyage). Thomson is one of a few cruise lines where tips are not expected. Yet, whether serving diners in the really quite swish Compass Rose restaurant on Deck 4, cleaning the cabins or endlessly polishing the handrails, the crew were unwaveringly friendly and cheerful. In fact, probably the only grump on the whole ship was the tenant of cabin 522.

One reason for my temporary ill-humour was the discovery of a sudden change of itinerary. A surprising aspect of hitch-hiking, I discovered, is this: although it is an activity in which you are wholly dependent on generous souls, you actually have more control over where you go than when you board a cruise ship. For example, when I hitched to Athens in 1975 there was no chance I would instead arrive on the island of Santorini. However, on arrival in Corfu, the passengers on Thomson Spirit learned that the shipping line had been outmanoeuvred.

The planned call in Santorini could not take place on the appointed trip, due to other cruise ships barging in on that day and rendering shore excursions unworkable. So we would go straight there from Corfu rather than to Piraeus, the port for Athens. Which was unfortunate, because of the Acropolis.

The high town that shines down on congested, sclerotic Athens combines antiquity, artistry and geometry, manifest in the perfect proportions of the Parthenon. But currently this temple to Athena is a right old mess, with portable buildings where the columns should be. So top of my list – and, I daresay, many other passengers aboard the Thomson Spirit – was the new Acropolis Museum. The abrupt change of course meant we arrived, inconveniently, on a Monday. And despite the economic meltdown afflicting Greece, the authorities refuse to open the doors to tourists on the first day of the working week.

The intransigence of the museum was not, of course, the fault of the Thomson Spirit. And the change to the schedule? A spokesperson for Thomson later told me that "Whilst we do not expect to deviate from our latest published schedule, we cannot guarantee this – just as no other cruise line can. There are numerous factors that influence our ability to operate as scheduled, not all of which are within our control."

Sailing from Piraeus in peak season demands your attention on deck. Forget Dover Eastern Docks: this is a maritime game of chess that gets ferries, the ageing hydrofoils that rejoice in the name of Flying Dolphins and cruise ships the size of Ayers Rock in and out on time (or, in our case, a day late).

The Thomson Spirit takes an interesting route from Piraeus to Crete. Most mariners would steer south-south-east. But Captain Skourlis headed due east. To Turkey.

A call at the resort of Marmaris was always part of the plan. It offers the chance to explore the tangle of lanes and staircases in the old town that clamber up to the top of the hill (follow the signs to the Castle Café for the finest view with excellent tea and, should you need it, Wi-Fi). Most passengers and a good few crew took advantageV C of what was rumoured to be the cheapest shopping in the eastern Mediterranean. But the main reason for such a radical diversion was fiscal. Calling in at one non-EU port renders the whole cruise duty free, increasing the profit margins for the ship and cutting the cost of goods in the on-board shop.

The modest retail offerings comprise one of the rare opportunities for Thomson to make extra revenue; the other leading earners are drinks (except for passengers who had paid extra for unlimited alcohol) and shore excursions.

The excursion desk is one place where the staff are actually employed by Thomson, selling coach trips such as "Panoramic Crete" (£41) and "Athens On Your Own" (£16, for a bus into town and back). They also, to their credit, freely offered expert advice on each port of call to independently minded (or, in my case, stingy) passengers. The grand total of Thomson employees on board: six. The cruise business seems to be the ultimate in outsourcing, with barely 1 per cent of the crew directly employed by the firm whose name appears on the funnel.

Considering that hardly anyone on board actually works for Thomson, their dedication to the cause is remarkable. All the entertainments staff – musicians, singers and dancers – are supplied by an agency named PEEL, based in North Yorkshire. The team is led by Ray Bauer. He is the on-board face and voice of Thomson. Even though it is a German company, Thomson does not exactly promote the fact that its cruise director is a German comedian. Funny, that. But Bauer the Bavarian, as Ray quickly and inevitably became known, was great value before and after the twice-nightly shows in the Broadway Lounge.

Ray, and Thomson, are serious about providing high-quality entertainment. He travelled to Brazil to audition dancers and to Manila to find hard-working and talented musicians who would work from noon to midnight, and on "changeover day" – each Friday in Corfu – bid farewell to departing passengers and greet the new arrivals. You could tell which was which because the new lot were significantly lighter.

The Thomson Spirit is a mobile all-inclusive holiday. The hub of the feeding frenzy is the Lido buffet, a self-service food station on Deck 5 that closes for only 90 minutes in every 24 hours. Don't panic, you are not going to starve during this hour-and-a-half because another outlet is open.

The meals were as impressive in quality as much as quantity, though cruise snobs might be disappointed by the smoked fish being mackerel rather than salmon, and could complain that the orange juice had enjoyed only a passing acquaintance with fresh fruit. And while the manifest for the Titanic boasted 400 asparagus tongs and 1,500 grape scissors, the statistics for the Thomson Spirit are more prosaic: weekly consumption includes 18,850 teabags, 28,500 portions of butter and 87 bottles of gin. That's two cups of tea and three little slabs of butter each day for every passenger, and a decent drink for the captain (my joke, not Ray's).

The approach to Crete at sunrise was more delicious than dinner, and lasted longer. The Thomson Spirit threaded through the dawn, between rocky collosi and nosed up to the bobbing boats, painted with the primary colours beloved of postcard vendors, in the harbour of Agios Nikolaos.

Once a hitcher... I wanted to complete a journey I had never finished in 1975, to the lonely island and former leper colony of Spinalonga. As the coach groups assembled, I obstinately started thumbing along the coast. The third car was a taxi, on its way to a pick-up in the village of Elounda, so we settled on half the normal fare. The Mercedes wafted over the headland and drifted down to the place where a boat was waiting to cross to the isle.

It was still early, an hour before the tour groups would arrive, and the church, homes and café were almost deserted. I roamed around defences that had a familiar feeling to them – those fortifying Venetians again – and then headed back to the indolence and indulgence of the Thomson Spirit. What's the time? Ah, yes, meal time.

Travel essentials: Pearls of the Aegean

Simon Calder paid £707 per person for a family of four aboard the Thomson Spirit cruise "Pearls of the Aegean". He booked through a cruise specialist working for Future Travel (0800 883 0411). The price included flights from Luton. The cruise started and ended in Corfu and visited Santorini, Piraeus (the port for Athens), Marmaris, Agios Nikolaos in Crete and Kefalonia.

Next summer, the call in Santorini will be replaced by the island of Mykonos.