A new fleet of Caledonian Sleeper trains, with double beds and en-suite bathrooms, have been unveiled and transported passengers for the first time.

Passengers and special guests boarded one of the new trains for its maiden journey between Glasgow and Edinburgh before they are rolled out by the end of May.

Built at a cost of £150 million, the new fleet will be the only sleeper service in the world to offer double beds, with further additions including reclining seats, a hotel-style keycard system and onboard WiFi.

The 75 new carriages will be replacing rolling stock built in the 1980s, travelling overnight between London and 40 Scottish stations.

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In addition to the new double rooms, passengers can choose solo or twin club rooms with an en-suite, classic rooms with one or two single beds, or reclining seats. The number of accessible rooms, for passengers with reduced mobility, has also been increased.

Prices range from £45 for seats to more than £300 for a superior double room.

Following delays to the delivery of the new fleet, managing director of Caledonian Sleeper said staff were "beside ourselves with excitement about the launch of the new trains."

Mr Flaherty said: "The current rolling stock is nearly 40 years old so the new trains come with a whole new level of comfort and facility that the modern traveller expects.

"We've changed our approach completely, when Serco took over we realised that it needed to be a hospitality experience rather than just a functional overnight.

"We are blessed with really good staff who offer a really warm welcome, we've now a really comfortable, modern train and that's supported by a really interesting food and drink offer, so actually we are the smart choice for people travelling between London and Scotland."

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He added: "There's something quite magical about going to sleep at one end of the country and then waking up - whether it's waking up in the capital in London, whether it's waking up in the Highlands - it's just a tremendous experience."

Since 2015 the Caledonian Sleeper franchise has been run by Serco, whose chief executive is Rupert Soames - the grandson of Sir Winston Churchill.

Speaking on board, Mr Soames said: "I'm the third generation of my family to be travelling on the Sleeper, my grandfather used the Sleepers, my parents used the Sleepers and one of my earliest memories is coming up to Scotland in the Sleeper and sleeping head to toe with my sister in the train.

"It's a wonderful way for families to travel."

He added: "They've been redesigned from the wheels up. All the beds have been redesigned, it's the only service in the world that has got double beds.

"It's got double beds, it's got single beds, bunk beds, we've got loos and showers en suite in the bedroom.

"We've then got this lounge bar which I think is going to be the centre of a lot of craic, a lot of fun."

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Rail historian David Meara described the Caledonian Sleeper, which has been running since 1873, as a "magical experience", adding: "This service has a very special place in people's hearts."

"While on the continent sleeper trains are slowly being phased out, because long-distance train travel is so much easier with the high-speed routes, yet in this country because of the investment of Serco and the Scottish Government, the Anglo-Scottish sleeper service is set to have a new renaissance," he said.

"We're going to get these brand new sleeper carriages - the mark fives - which I think take the service to a new level of luxury.

"They are very smart, very light, very airy. They've got more bells and whistles.

"The double bed, the en suite, the WiFi - all the things modern travellers like when they are having a hotel-style experience as they travel on the train.

"The introduction of en suites in some of the cabins is an absolute bonus and it means that for a lot of people it becomes a much more attractive way of travelling long distances between England and Scotland."