Between 10 and 13 million people from across the world, including around 2.5 million Britons, visit the Greek islands every year and the freedom to board a ferry and hop from place to place as casually as you get on a bus at home is one of the big attractions.
But the disastrous sinking of the Express Samina, carrying up to 530 passengers, has highlighted fears about the safety of some of the ageing vessels that ply Aegean waters.
Guidebook Greek Island Hopping achieved Cassandra status this week, when it emerged that it had warned readers for many years about the Express Samina. "Arguably the worst Greek ferry afloat. A large grime bucket with a reputation for running late," it said.
The book's author Frewin Poffley described the tragedy as "an accident waiting to happen", but advises travellers not to panic, as the Samina, built in 1966, is no longer typical of the island ferry fleet.
The past few months have seen the biggest shake-up in the Greek ferry fleet in over two decades, he says, with a series of major take-overs and a succession of new boats appearing. "The investment is actually coming in. That's why this accident is so tragic. This boat is not really typical of the Greek ferry fleet anymore - it might have been 10 years ago, but now it's a dinosaur."
The question of human error is looming large in the criminal investigation now underway, which will examine reports that the crew was watching football on television when the vessel ploughed into rocks. Poffley says: "If the reports are true that the crew was watching television, then it is not the age of the ship that was crucial, though it is obviously a factor."
The 1960s design of ships like the Samina - with a comparative lack of exit facilities - impedes escape in a rapid sinking. The only exits for deck-class passengers are at the stern; other doors are usually kept locked on vessels of this age to prevent deck-class passengers invading higher ticket-price areas.
The difficult task of establishing how many were missing in the tragedy off Paros has been exacerbated by the ticketing system, under which passengers were able to buy tickets on board, while tickets were not issued to small children. A computerised system was brought in a few years ago in response to serious overcrowding problems - but its application remains hit-and-miss.
Poffley says: "Greek boats are almost like buses, you just get on. That is something that is going to have to change. The system exists but - Greece being Greece - no one implements it terribly well until something like this happens."
Other boats criticised in Greek Island Hopping
• The Express Samina's sister ship, the Naias II, now renamed the Express Naias and running from Piraeus to Mykonos. "The Naias II is a boat to be avoided at all costs. Sister to the equally awful Golden Verginia [former name of the Express Samina], she is just as slow and grimy and is - for many tourists - a less than happy introduction to the Greek ferry system . . . She was pilloried in a ferry safety report published on the internet - though these problems have now been resolved."
• The Karistos, built in 1968: "A tiny Greek-built ferry that rattles daily between Rafina and Karystos on Evia . . . if she wasn't providing an 'essential' link service she would be a leading candidate in the 'next tub for the scrapyard' stakes; as it is, she is set to crawl for another five years."
• The Agios Rafail, built in 1968:"Arguably the least comfortable major ferry in the Aegean . . . the experience is something like being on a cross between the back of a floating lorry and a building site."
• Greek Island Hopping is published by Thomas Cook Publishing at £12.99.
