The move came days after opposition to abolishing the age-old practice was highlighted by Scotland on Sunday, The Scotsman’s sister paper.

Operator Serco had planned to force all passengers travelling alone to pay for their own cabins, like those travelling first class.

That would have increased such fares by two-thirds, from a minimum of £85 to at least £140. Serco intended to make the change this month, but has shelved it until the first of a new fleet of trains starts running.

The Caledonian Sleeper from London Euston to Edinburgh Waverley with guests travelling up for the Edinburgh International Fashion Festival. Picture: Greg Macvean

These were due to enter service in April but are not now due until October because of design and production problems at a factory in Spain.

The most vociferous opponents of the change were sleeper passengers in the Highlands, who said sharing a cabin made the overnight trains to London affordable.

They have also pointed out that railcards will no longer be usable by people travelling together who share a cabin, although this has also been postponed to the autumn.

A petition has been launched on the 38 Degrees website.

It is believed that sharing with a stranger of the same sex has been a feature of Scotland-London sleepers since they were introduced 145 years ago.

Sharing is still permitted on Britain’s only other sleeper, the Night Riviera between London and Penzance.

Julian Paren, who led the campaign against the move, said: “I welcome the announcement of a return to the original pricing structure for railcards and the share with a stranger option after 25 February, but deplore the confusion in how this will be implemented.

“For those who wish to share with a stranger, no bookings can be made until 25 February, even for travel the next day.

That is the reality of the inflexibility of the booking system.”

Glasgow passenger Katherine Jones tweeted: “This is disappointing. I have never had a problem sharing on  @CalSleeper when I travel for work, to keep the cost (£ and environmental) down.”

But the Fact Compiler tweeted: “Shurely @calsleeper recognises need for personal privacy and ends outdated practice of sharing with strangers!”

Serco claimed fares for passengers travelling together who shared a cabin would be cheaper in the new trains than the current fares with a railcard.

Caledonian Sleeper marketing director Iain Baxter said: “We are sorry for any confusion over the introduction of our new trains’ fares structure, which results in the removal of the ability to share accommodation with a stranger in standard class.

“Originally, we were intending to cease offering these fares in February but now we have a confirmed date of October for the introduction of the new trains (on our Lowland routes from Edinburgh and Glasgow) we are able to reinstate existing fares until the new trains are running. Use of railcards will also remain unchanged prior to this date.”

The Scottish Government’s Transport Scotland agency, which agreed to the changes in Serco’s contract, said just four people per train choose the “outdated” sharing option.

Caledonian Sleeper postpones ban on strangers cabin-sharing