A P&O price promise, made to customers who book their cabins well in advance, has been criticised by passengers.
The P&O website explains how the guarantee, which was introduced last July, is designed to protect customers who prefer to make early bookings. It reads: "The Price Promise is designed to give you the confidence to secure your booking early, safe in the knowledge that if P&O cruises were to reduce the Vantage Fare for a holiday you have already booked, we will pass on the value of the reduction to you automatically in the form of a complimentary benefit such as on board spending money or a cabin upgrade."
However, some disgruntled passengers have complained that even though they have seen the same cabins selling for less than half the price they paid, P&O will not honour the Price Promise because Vantage Fares and last-minute, discounted 'Getaway' fares are not comparable.
BBC News reports that a number of listeners have complained to Radio 4's Money Box programme, including one couple who discovered that their holiday was being sold for £500 per person less, by the time they set sail.
Ray Blackmore and his wife Wendy, from Somerset, paid £949 per person for a cruise to the Norwegian fjords last October, and booked six months in advance. However Mr Blackmore later became concerned that he had paid more than necessary.
He told Money Box: "We suddenly saw the same cruise, the same cabin, being sold at reduced rates. It eventually went down until it was £500 cheaper. The price promise doesn't appear to happen."
When he wrote to P&O to request a refund, the company refused.
Money Box put the Blackmore's case to P&O, but a company spokesperson explained why they weren't entitled to a refund.
The spokesperson said: "We all appreciate how frustrating it is to make a purchase and then see a lower price, especially on a premium product such as a holiday.
"With Vantage fares, passengers pay a 15 per cent deposit, are able to choose the cabin type, location and number, and can choose from an additional benefit such as on board spending money or complimentary car parking.
"When bookings are made on a Getaway fare, passengers are not able to select the cabin type or location and there are no additional benefits.
"In our future advertising campaigns, we plan to promote Getaway fares alongside Vantage fares. This allows the customer to make an informed choice about the promotion and the associated benefits of each fare."
Click on the image below to see the top 10 cruise destinations...
Top ten cruise destinations
P&O passengers criticise Price Promise offer
Perfect for: A jam-packed itinerary.
The Western Mediterranean is all about seaside (Barcelona, Cannes) as well as glamorous party spots, such as Ibiza and Malaga. On top of that, a cruise will take you to some of the most iconic attractions of the world in the likes of Rome, Valencia and Florence...
Perfect for: Lovers of beauty, peace and tranquility.
It has been said that the only way to truly appreciate the wonderful scenery of Norway's fjords is to sail through them. With long light summer evenings, pretty ports of call and one-of-a-kind natural wonders, it's easy to see why the Norwegian fjords are popular among cruisers.
Perfect for: Something a bit different.
From extravagant art and architecture in Russia to imposing towers and medieval streets in Poland, the Baltic offers enthralling skylines and wonderful scenery that is still relatively undiscovered by Brits. Must-see attractions include Copenhagen, the famous Ice Bar in Stockholm and the majestic Hermitage Museum in St Petersburg.
Perfect for: Year-round warmth and sunshine close to home.
Highlights of a Canaries cruise include extraordinary volcanic landscapes, beautiful beaches and quaint whitewashed villages on the islands of Lanzarote, Tenerife and Gran Canaria. Think beautiful black and white sand beaches, volcanoes, sand-dunes, verdant slopes and blue seas...
Perfect for: Exploring the bits of Europe you don't usually see.
Highlights of an Eastern Med cruise include relatively undiscovered bits of Croatia, Bulgaria and Ukraine as well as some best-loved destinations such as Greece and Turkey. Don't miss the bustling bazaar and mosques of Istanbul, swimming in the clear sea in Croatia, sampling the delicacies of the Greek islands and the sights of medieval Montenegro.
Perfect for: A real taste of the Far East.
How else can you explore Thailand, Japan and China in one holiday? This is your chance to visit remote mountains and paddy fields as well as cosmopolitan cities such as Tokyo, Bangkok and Singapore. One of the best destinations for culture, scenery and exotic history.
Perfect for: Adventurous types.
Australia and New Zealand are on many Brits' wish list - and on a cruise holiday, you don't have to choose between the two. Take in the mountains, coastlines, lakes, fjords, alpine glaciers and volcanoes of New Zealand as well as Australia's vibrant cities, modern buildings and fine restaurants. Oh, and this part of the world was made for rafting, climbing, bungee jumping, hiking...
Perfect for: Short cruises.
Most people imagine sailing off to a far-flung, exotic destination when planning a cruise holiday, but did you know you can enjoy a cruise around Britain and Ireland? Mini cruises are all the rage these days and there's a variety of beauty spots to see right here - plus with less time on the cruise ship, you'll have more time to explore! Visit the Channel Islands (think fabulous seafood, beaches and nature), as well as Ireland and North Wales, where you'll get plenty of wildlife viewing opportunities, with seals, dolphins and even puffins to spot.
Perfect for: A once-in-a-lifetime holiday.
If you feel you've experienced the Caribbean and Mediterranean, Panama Canal is a fabulous option for cruisers craving a taste of adventure. Highlights include watching as the cruise ship sails through the locks just inches from the canal's sides and looking out at the wild jungle beyond. Don't miss whale watching and spotting tropical birds.
Perfect for: Romantic types and sun worshippers who just want to chillax.
With its paradise islands, turquoise seas and sugar-soft beaches, this is the most popular cruise hotspot of all. Barbados, the Dominican Republic and the British Virgin Islands are just a few of the islands to get some R&R. Soak up the famous laidback lifestyle, visit the bustling markets and dance under the stars. Bliss.