“They can keep saying that, and we can keep proving them wrong.”

That was the response of Saudi Arabia’s Crown Prince Mohammed bin Salman in a TV documentary broadcast in July 2023, while talking about scepticism surrounding Saudi Arabia’s flagship construction projects.

Almost a year later, some of the doubts are turning out to be true. In recent months, Saudi Arabia has seemingly scaled back plans for its vast desert development project Neom, which is the centrepiece of Vision 2030. This is the economic diversification programme spearheaded by Prince Mohammed, the Gulf state’s de-facto ruler, to transition the country’s economy away from oil-dependency.

As well as Neom, Saudi Arabia is also developing 13 other large construction schemes, or “giga projects” as they are referred, worth trillions of dollars. These include an entertainment city on the outskirts of the capital Riyadh, multiple luxury island resorts on the Red Sea, and a cluster of other tourist and cultural destinations.

But low oil prices have impacted government revenues, forcing Riyadh to reassess these projects, and explore new funding strategies. An advisor, who is associated with the government but wished not to be named, tells the BBC that the projects are being reviewed, with a decision expected soon.

“The decision will be based on multiple factors,” he says. “But there is no doubt that there will be a recalibration. Some projects will proceed as planned, but some might get delayed or scaled down.” Announced in 2017, Neom is a $500bn (£394bn) plan to build 10 futuristic cities in a desert region in the north west of the country. The most ambitious of them, and the one that has gained all the headlines, is The Line. This will be a linear city consisting of two adjoined, parallel skyscraper walls standing 500m high - taller than the Empire State Building. Yet they will have combined width of just 200m, including the gap between them.

The original plan was that they would extend for 170km (105 miles), and become home to nine million inhabitants.

But according to people familiar with the details – and as already leaked to the press - the project developers will now focus on completing just 2.4km by 2030, as part of the first module. When The Line was first announced it was billed as a “carbon-free linear city” that would redefine urban living, with amenities for residents like parks, waterfalls, flying taxis, and robot maids. The city would have no roads or cars, and would be made up of interconnected, pedestrianised communities. It would also include an ultra-high-speed train, with a maximum journey duration of 20 minutes anywhere within city limits.

How many of these features will be part of the first phase are unclear. Along with The Line, Neom is also due to include an octagon-shaped floating industrial city, and a mountain ski-resort that will host the Asian Winter Games in 2029.