Hollywood actor Idris Elba has a "big dream" for Sierra Leone, the West African nation where his father was born - to regenerate a beautiful island off its coast and turn it into an eco-friendly "smart city".

"Originally we went there thinking how could we bring tourism to the most incredible 19 miles of beachfront," the British star told the BBC about Sherbro Island.

But as the idea was explored, a more innovative plan came into play - to bring in partners and seriously develop the area in a sustainable, eco way. The project now also intends to bring wind-powered renewable electricity for the first time to Sierra Leone.

"It's a dream, you know, but I work in the make-believe business," says Elba, best known for his roles in Luther, the Wire and for playing Nelson Mandela. The 51-year-old actor wants to make people believe this can happen - and change perspectives.

"It's about being self-reliant, it's about bringing an economy that feeds itself and has growth potential. I'm very keen to reframe the way Africa is viewed… as an aid model.

"This opportunity is completely different."

Idris Elba was brought into the project by his childhood friend Siaka Stevens, the grandson of a former Sierra Leonean president of the same name.

The pair grew up together in east London, both have worked as DJs and their paths often cross in the entertainment world.

For the last decade, Stevens has been spending more time in Sierra Leone and had initially wanted to establish a boutique hotel there. However, he told the BBC his background in luxury hospitality and entertainment made him quickly realise "Sierra Leone wasn't ready for that level of tourism".

This is what spurred thoughts of developing Sherbro Island and with encouragement from a friend who worked on the Saudi Red Sea enterprise, a tourism megaproject, he approached Elba.

Idris Elba and Siaka Stevens are determined to preserve the beauty of Sherbro Island
Sherbro Alliance Partners

Two years later Sherbro Alliance Partners (SAP) was born and in 2019 a deal was struck with the Sierra Leonean government to develop Sherbro, which falls within the home district of current President Julius Maada Bio.

"We believe that Sherbro Island City will be an economic engine for our country and neighbours," the president said at the time.

The island had a population of around 30,000 people in 2013, when the latest available data was recorded - and is approximately 600 sq km (230 sq miles). That is a little bigger than the Isle of Man off the UK and about twice the size of Malta.

Stevens says development is to begin around the main town of Bonthe, but the whole island is within the scope of the project - "potentially accommodating a population of up to a million people".

However, Elba insisted "the character of the island hopefully will remain intact. It's a beautiful, green part of the world and we don't want to disturb that."

The project is to be financed through a public-private partnership, and the island will be designated a special economic zone with a separate legal and economic system from the rest of Sierra Leone.

Stevens likens its status to that of Walt Disney World in Florida. In addition to tax incentives, Disney was granted regulation exemptions and significant autonomy over planning.

The wind and solar farm, to include five wind turbines, an array of solar panels and battery storage, will be built by Octopus Energy Generation, one of Europe's largest investors in renewable energy.

Stevens says their involvement was secured after Elba and his wife Sabrina met top Octopus officials Greg Jackson and Zoisa North-Bond at a party where they were "super interested" in Sherbro.

Octopus said construction was scheduled to begin later this year, though the timing depends on weather conditions. Sierra Leone's rainy season typically runs from May to November.

The company says "onshore wind and solar power are some of the quickest sources of energy we can build" and the windfarm should be complete in a matter of months.

Idris Elba and his Sherbro partner Siaka Stevens (L) have signed a deal with Octopus Energy to build Sierra Leone's first wind farm
Getty Images

This is an exciting prospect for Sierra Leone, where only 28% of the population currently has access to electricity - and rural areas like Sherbro Island have no main power.

Ms North-Bond, head of Octopus Energy Generation, told the BBC the company was considering two ways to distribute power across the island.

One was a micro-grid. The other was to function as an "energy island", enabling local businesses to bring electric vehicles - both cars and motorcycles - to charge up from on-site battery stations and then deliver energy to domestic batteries in people's homes.

Octopus's work on Sherbro Island was a pilot and would serve as an exercise in data collection and potentially a model for other parts of Sierra Leone or elsewhere on the African continent, Ms North-Bond said.

On the wider vision for Sherbro, Stevens told the BBC he wanted it to be an "Afro-dynamic eco-city" to be based on African cultural values, prioritising community, collaboration and respect for nature.

It should also be able to adapt to changing social, economic and environmental conditions and be built sustainably - an energy-efficient set-up, resilient to climate change.

As the coordinator, Sherbro Alliance Partners has not specified a single budget, but investment would be drawn from a wide range of sources and is likely to run to billions of dollars.

In addition to the partnership with Octopus, it has signed contracts with a series of specialist partners including:

• Lloyds will "support economic growth opportunities" and provide expertise on insurance and risk
• Sasaki Associates and Foster & Partners will oversee the overall master plan and landscape architecture. Fosters is renowned for a wide range of global projects including London's Gherkin, City Hall and Millennium Bridge
• MIC-HUB, a transport planning company, has been charged with administering efficient transport to and from the island, along with eco-friendly travel on Sherbro
• And coastal engineer PRDW is to consider climate change impacts and how sea level variations may impact the island.

The success of this project can only be judged with hindsight, but it is a huge undertaking.

Some other African projects with a similar ethos are yet to reach their potential. There have been questions about the feasibility of Senegal's Akon City or the Malaysian Eco-Satellite City in Uganda.

But in Sierra Leone, the metric of success goes way beyond the bottom line. Elba seems doubtful about ever turning a profit - but as he said, it is about making it work.

"Part of me wants to build that beautiful retirement home for my mum," he said.

"Never in my lifetime would I have thought I could build the foundation for a new smart-city... I'm not qualified for that. But I am qualified to dream big."

Reflecting on his late father, Elba said he would probably think the dream was too big, but he would be proud and have some sound advice: "If you're going to do it, make sure you do it properly.

"You do it good, you do it with all your heart because that's the best you can do."