As Jack and Dani are crowned the winners of this year's Love Island, sailing away with the 50,000 top prize, another race is firmly under way.

The reality show's fourth season has been a huge hit for ITV - not only in ratings terms but commercially as well.

The programme has raked in tens of millions for ITV, which also makes it.

Other production companies and channels now want a piece of the action and are trying to devise their own rivals.

That could be easier said than done, however. Tom Harrington at Enders Analysis says "everyone is trying to emulate the success of Love Island", but coming up with a hit format is one of the hardest tasks in television: "It's like alchemy."

It's also impossible to say exactly why the show has become a must-watch for the 16 to 34 age group, he adds.

About one in two people in that bracket has seen some of the show during its six nights a week, month-long run on ITV2, giving huge exposure to the companies that have sponsored it. They include Superdrug, fashion retailer Missguided, music and club brand Ministry of Sound and Kellogg's.

The 16-34 audience watches far less "live" television - as it is broadcast - than older viewers, making them particularly difficult for advertisers to reach via the small screen, says Steven Ballinger, managing director of commercial and trading at Carat, an advertising agency owned by Dentsu Aegis.

He estimates that advertisers are paying between 30,000 and 50,000 for an advertising slot on Love Island this year - considerably less than the 150,000 for an ad during the X Factor on ITV's main channel.

But as well as selling the hundreds of ad slots, brands would have paid at least 1m to become a sponsor, Mr Ballinger tells 5 live's Wake Up To Money. He thinks Superdrug will have forked out in excess of 4m for its third year as headline sponsor.

Love Island has become an "influencer brand that enables other brands to borrow the 'equity' of the show", Mr Ballinger explains. "I think it is the future - broadcasters like ITV need to diversity their revenue streams."

ITV also stands to make tens of millions selling the rights to the show to broadcasters in other countries, with a total of seven sales so far.

"Formats are the holy grail in television," Mr Harrington adds.

International versions of Love Island and singing contest The Voice helped drive a 55% rise in "rest of the world" revenues for ITV Studios to 247m in the first six months of 2018.

Sales from its programme-making division - whose other shows include Coronation Street, Poldark, Loose Women, Dancing on Ice and Queer Eye - rose 16% to 801m and now account for just over half of ITV's total external revenue.

Then there is merchandise: viewers can buy personalised Love Island water bottles, phone cases and wash bags through the app, which can also be used to vote for their favourite contestants; play the Love Island game on their phones; or listen to the daily podcast.

"Part of ITV's strategy is going to direct to consumers with some of their brands and TV shows to diversify their revenue streams," Mr Ballinger adds.

And if that's not enough you can even visit the Love Island beach at Thorpe Park.

While Dani Dyer and Jack Fincham are tipped to win tonight - and potentially make millions from social media endorsements and appearances - even those who spent very little time in the villa stand to make six-figure sums as well.