For the last 40 years Marvin Gaye has enjoyed a level of enduring fame which he shares with only a handful of other artists “ like Elvis, or the Beatles.

They began their careers cutting records on vinyl discs, lived on through the eras of tape cassettes and CDs, and continue to thrive in the age of digital streaming.

It Is 40 years since Marvin Gaye died in Los Angeles “ shot dead by his father in the middle of a violent domestic dispute.

But his music is still streamed and downloaded around 20 million times a month, and his classic duet with Tammi Terrell, Aint No Mountain, has been streamed more than a billion times.

So the value of a cache of audio tapes containing new material recorded by Marvin Gaye could be huge.

Theyre part of a strange treasure trove of material associated with the star which lay hidden in Belgium for more than forty years, but which may now be about to make global headlines.

The story of Marvin's Belgian connection has been told before.

He was living in London and becoming a heavy user of cocaine when he met a Belgian concert promoter in a nightclub. He took the promoters business card and a week later called and arranged to move to the coastal city of Ostend.

Its not an exaggeration to say the move may have saved the singers life.

He got fit again, jogging and cycling on the flat North Sea landscape, and he returned to the studio, recording one of his greatest hits, Sexual Healing.

For a time he lived in the home of a Belgian musician, Charles Dumolin. The collection of stage costumes, notebooks and tape cassettes is now in the hands of Charles family.

But now the BBC can disclose the intriguing possibility that Marvin may have recorded previously unheard new music in the same period, which has lain hidden in Belgium for more than forty years.

Belgian lawyer Alex Trappeniers, whos a business partner of the family who lay claim to the material, is in no doubt that the fate of a hugely valuable collection of stage costumes, notebooks and never-before heard music is about to be decided.

Speaking exclusively to the BBC, he explained the legal position as he sees it.

They belong to [the family] because they were left in Belgium 42 years ago, he says. Marvin gave it to them and said, ˜Do whatever you want with it and he never came back. Thats important.

At the heart of this story though is that new, never-before heard music.

Alex played us a brief, tantalising sample of Marvin rehearsing. In a rather eerie moment, the Prince of Motown almost seemed to live again.

He and his backing musicians deliver a complex sequence of harmonies and the great man says self-deprecatingly: Was the tape-recorder on? Im not sure I could do that again.

The task of getting the recordings into some sort of order was huge, but it gives a clear hint as to how big “ and how important “ this find could be.

Each time a new instrumental started when Marvin started singing, I gave it a number, Alex told us. At the end when I had listened to all the 30 tapes I had 66 demos of new songs. A few of them are complete and a few of them are as good as Sexual Healing, because it was made in the same time.

One new track above the others makes Alex think we might hear another global hit from Marvin Gaye in the future “ just think of the way in which relatively primitive recordings of the Beatles were salvaged and remastered to create their final hit Now and Then.

Alex wouldnt play us the song “ he hasnt even played it to his wife “ but he says simply: There was one song that when I listened to it for ten seconds I found the music was in my head all day, the words were in my head all day, like a moment of planetary alignment.

On a more practical level, theres no doubt about the authenticity of the archive.

We spent an afternoon in a private room in a concert hall in Ostend flicking through page after page of documents revealing every aspect of Marvin Gayes life at the time.

There are typed running orders for concert performances, angry letters to his record company, drafts of lyrics for new songs and notebooks filled with private thoughts.

The BBC has seen a rack of Marvin Gayes clothes and costumes, including the unmistakeable red suit which he wore on tour. They are, we were told, just a small sample of the total.

But above all there is the music.

We sat, spellbound, looking out at the Ostend promenade where Marvin used to enjoy jogging as we listened to the startling purity and power of that voice in studio recordings which had never been heard before.

It was a spine-tingling moment, and Alex Trappeniers is in no doubt of its potential value.

We can open a time capsule here and share the music of Marvin with the world, he said. Its very clear. Hes very present.

But of course stories about intellectual property and music publishing rights are rarely straightforward.

Marvins apparent decision to gift this material to Charles who died in 2019 does seem to mean that the collection belongs absolutely to the Dumolin family.

On top of that, Belgium has a rather unusual law which stipulates that any property, however you acquire it, even if you steal it, becomes absolutely yours after a period of 30 years.

So far, so clear.

But that Belgian law doesnt apply to intellectual property.

So Alex Trappeniers and his partners could end up as the owners of the physical tapes on which the music was recorded, without the right to publish the songs.

And the heirs of Marvin Gaye in the United States could find themselves with a theoretical right to exploit the music, but with no way of accessing the music “ because they dont own the tapes.

In Alexs view the case for some kind of compromise is obvious.

I think we both benefit, the family of Marvin and the collection in the hands of [Dumolins heirs]. If we put our hands together and find the right people in the world, the Mark Ronsons or the Bruno Mars¦. Im not here to make suggestions but to say OK, lets listen to this and lets make the next album.

The level of secrecy surrounding the disclosure of Marvin Gayes Belgian archive makes it hard to judge what the global impact of the collection might be.

More important still of course will be the question of how all this is received by Marvin Gayes children, Marvin III, Nona and Frankie, and by the administrators of his estate.

We reached out to the Gaye family for a response. Lawyers for two of Marvin Gayes three children are now aware of the existence of this Belgian collection. It's possible that negotiations may follow, but they havent started yet.

A compromise might be reached between the owners of the physical tapes on the one hand and the owners of the rights on the other.

Morally there may be people reading this who feel that the collection of documents, costumes and recordings belongs to the Gaye family and should simply be handed over to them.

Alex argues that the legal situation just isnt that straightforward, and that he and his partners have the right to simply sell the whole collection.

Morally, he says, Id like to work with the family but this is the nightmare for them¦ that someone comes from a country where theres a lot of money and we make an agreement and this collection leaves this country.

If that happens, says Alex, thered be nothing to stop a buyer from exploiting the music of Marvin Gaye and passing it off as his own. An extraordinary possibility “ but he insists, a real one.

Forty years on from his short life and tragic death, Marvin Gaye could once again find himself at the centre of one of the biggest showbusiness stories of the year. (BBC)