Harmony of the Seas is still “a construction site”, according to its first paying passengers.

The world’s biggest cruise liner earned the world’s biggest headlines for its launch – but not all of them were favourable.

She left Southampton for Rotterdam on a four-night cruise three days ago, but customers complained attractions were closed and workmen were still busily putting things in place.

The BBC quoted passenger Georgina Davie, who described “queues of complaining guests and distressed families”. On social media, there was more bad news.

Passenger Jonny Hardy tweeted: “Really not pleased work is still going on when they have over 6,000 passengers.”

Ms Davie went further, contacting the BBC suggesting there might be danger to passengers. “Ninety percent of the kids attractions that it was marketed for have been shut for the whole cruise and are still being worked on.”

A Royal Caribbean spokesperson in Europe said the trip was for normal paying passengers.

“Whilst the majority of the ship’s features are open and already being enjoyed by thousands of guests, as with any new build, we are still making some final finishing touches,” the BBC quoted him as saying.

“These early sailings were made possible due to the early delivery of the ship and we hope this has been reflected in the great value offering guests secured for their holiday.”

The ship can carry 6,780 passengers. It has 20 restaurants, 23 swimming pools and took more than two-and-a-half years to construct.

The ships is due to leave the UK for Barcelona on 29 May.

A BBC analysis was somewhat kinder to the new ship, putting the complaints in contest.

Paul Clifton, the BBC’s transport correspondent in Southampton, said: “It’s quite normal for new cruise ships to have teething trouble and shipbuilding schedules are so tight, I’ve often seen workers laying carpets and hanging picture frames just hours before the first passengers get to their cabins.

But that should change when people get on board for their holidays. They have paid for luxurious facilities and high-class entertainment.

That’s why we have seen dozens of disgruntled travellers taking to Twitter – they feel let down.”