When cruise holidays began in the mid-19th century there were first, second and even third-class cabins.But in the more egalitarian post-Second World War period, ‘classes’ were largely dropped – until now.Cruise lines have been bringing in exclusive sections where only customers who pay extra are allowed access to perks such as private pools, lounges, restaurants and butler service.So, here’s our guide to the new ‘ship-within-a-ship’ world. Cruise lines have increasingly been introducing exclusive sections for the highest paying customers. Here’s our guide to this ultra-exclusive worldNorwegian Cruise Line: The HavenAn infinity pool to the aft of the latest Prima Plus-class ships is the newest addition to The Haven, a sanctuary with outdoor relaxation areas, a sauna and glass-walled cold room.Every suite has 360-degree sea views and butler service, while two-storey, duplex Haven Suites have huge living areas, three-bedrooms, three bathrooms and a large balcony.Top Perk: Concierge for speciality dining, front-row theatre seats and excursions.Book it: Seven-day ‘Caribbean: Great Stirrup Cay, Dominican Republic and Tortola’ cruise on Norwegian Luna departs Miami on August 15 from £3,190pp plus flights (ncl.com). Entry level price: £605pp. An infinity pool to the aft of the latest Prima Plus-class ships is the newest addition to The Haven, a ship-within-a-ship availability to Norwegian Cruise Line passengers Every suite has 360-degree sea views and butler service as well as huge living areas Cunard: Grill SuitesOn the newest Queen Anne ship, guests have access to the Grills Lounge and private Grills Terrace with a sundeck and whirlpool. There’s also butler service, a pillow menu and Penhaligon’s toiletries.Top Perk: A butler opens a bottle of Laurent-Perrier Champagne on arrival.Book it: Seven-night no-fly ‘Norwegian Fjords’ Southampton round-trip on June 20, 2027, starts from £5,018pp in Princess Grill Suites (cunard.co.uk). Entry level price: £829pp. On Cunard’s newest Queen Anne ship, guests can get access to the Grills Lounge and private Grills Terrace, where there is a butler service, pillow menu and toiletries from PenhaligonRoyal Caribbean: The GroveGuests have it all on 7,600-passenger Legend of the Seas which made its debut last month. The Grove, a private four-deck ‘Suite Neighborhood’, is the largest in the fleet, featuring a two-storey sundeck, pool, hot tub and VIP dining venues.Top Perk: The Suite Lounge with views of the AquaDome, where high-diving performances are held.Book it: Nine-night ‘Western Mediterranean from Barcelona’ departs September 24, 2027, from £3,399pp, including flights and a two-night hotel stay in Barcelona (iglu.com). Entry level: £1,729pp.Celebrity Cruises: The RetreatTop-paying guests on Edge Series ships get a butler and a specialist to help plan tours ashore and access to a private sundeck and lounge. The Iconic suites are the largest, sitting above the captain’s bridge with 360-degree views.Top perk: Dining in Luminae, with dishes by award-winning chef Daniel Boulud.Book it: Seven-night ‘Greek Isles & Malta’ cruise on Celebrity Xcel departs Barcelona on June 19, 2027, from £3,972pp plus flights (celebritycruises.com). Entry level: £1,415pp. Top-paying guests on Edge Series ships get a butler and a specialist to help plan tours ashore and access to a private sundeck and lounge (pictured)MSC Cruises: MSC Yacht ClubEnjoy a private lounge and bar, dining room, sun deck and pool with a bar. Benefits include priority embarkation/disembarkation, butler service and 24-hour concierge.MSC World Asia, launching in December, will have a two-deck, two-bedroom Royal Duplex Suite with a whirlpool bath on the balcony.Top perk: Access to MSC Aurea Spa’s thermal suite.Book it: Seven nights on MSC World Asia departs Barcelona on January 21, 2028, with fares from £1,824pp plus flights (msccruises.co.uk). Entry level: £669pp. Launching in December this year, MSC World Asia will have a two-deck, two-bedroom Royal Duplex Suite on board, with a whirlpool bath on the balconyVirgin Voyages: RockStarAccess to Richard’s Rooftop, an exclusive deck, is one of the bonuses with RockStar and Mega RockStar Quarters. There’s also free drinks, a bottomless in-room bar, free wi-fi and a priority laundry service.Top perk: Complimentary parking or private transfers.Book it: Seven-night ‘Alaska: Inside Passage & Glacial Fjords’ Seattle on Brilliant Lady departs August 20 with RockStar Quarters from £6,764pp plus flights (virginvoyages.com). Entry level: £909pp. The bonuses available to top-class passengers of Virgin Voyages include access to exclusive deck, Richard’s Rooftop, as well as a bottomless in-room bar, free Wi-Fi and a priority laundry serviceHolland America: PinnacleEnjoy verandas with hot tubs, a private club, concierge, early check-in, free laundry service and wi-fi with Pinnacle suites.Top perk: Luxurious Duxiana king-size beds made with natural materials.Book it: Seven-day Vancouver round trip on Koningsdam departs May 29, 2027, from £6,909pp plus flights (hollandamerica.com). Entry level: £1,171pp.Disney: Concierge SuitesGuests go to the front of the queue for shore tours, adult-exclusive dining reservations, spa treatments and nursery stays. The Concierge team is available 130 days before the sailing.Top perk: Access to dedicated Concierge Lounge and a private sundeck.Book it: Three-night no-fly Southampton round-trip to Zeebrugge, Belgium, on Disney Dream in a Concierge Royal Suite departing August 28 from £5,853 (disneycruise.com). Entry level: £1,117pp.