On 25th February 1940, "The Proud Valley" became the first film to have its première on radio, when the BBC broadcasted a 60-minute version.
The film starring the legendary Paul Robeson, was written by Herbert Marshall and his wife, Alfredda Brilliant, who were both associated with the Left-Wing Unity Theatre, and with a script from Welsh writer  and ex-miner  Jack Jones was filmed on location in the South Wales coalfield and realistically  portrays the hardship of an industrial community when representations of both the working class and ethnic communities were often broadly-drawn caricatures.
It tells  the story of a good natured and generous charismatic African-American  sailor called David Goliath, who arrives in the mining community of Blaendy in the  Rhondda Valley, Wales in 1938 in the aftermath of the 1926 general strike and the Great Depression who after finding work down the pits as a stoker wins the respect of the local Welsh people through his singing. 
Carousing his fellow workers with the song All Through the Night, he captures the attention of Dick Parry (Simon Lack) and his son Emlyn (Edward Chapman) whose dream is to win the national Welsh choir contest. He becomes a hero who sacrifices his own life, in utterly heartbreaking scenes, to save fellow miners in an underground accident.  
Robeson later remarked that, of all his films, this was his favourite, it enabled Robeson to express his socialist beliefs and portray the struggles of the Welsh working class  and both deepened his relationship with the Welsh working class and forged for all time their love for him.https://teifidancer-teifidancer.blogspot.com/2016/08/paul-robeson-941898-23176-and-people-of.html
The Welsh actors in the supporting cast, notably Rachel Thomas, Charles Williams and Jack Jones previously mentioned , give the film its authenticity. The setting of the film is realistic too. Some location work took place in te Rhondda Valley and working class life and death isn't glamourised.
The film was a politically radical story too even by today’s standards, 
tackling the difficult issue of coal pit closures – one that continued 
to resonate throughout the British coalfields throughout the century and
 made the film relevent to generations of mineworkers who faced the 
similar closure programmes decades on.
It was noteably sympathetic towards the plight of 
the miners, and also the crucial role that the coal industry played in 
mobilizing the populace for the coming war, which broke out as the film 
was reaching its final weeks of shooting. The producers even re-worked 
the ending to reflect this.
It also dealt bluntly with racism – At one point in 
the movie a group of workers complain about David’s (Robeson’ character)
 position in the mine and in the choir. “This fellow brought a black man
 to work down the pit…” “Well?!?” booms a voice from off-camera. “What 
about it?” In a close-up you see Robeson hang his head and stoop his 
shoulders, showing his emotional pain at the slight. But in the singing 
there’s a complete solidarity amongst the men which echoes the theme of 
the movie.
The film shows how the solidarity of the workplace overcomes the 
miners’ suspicion about a dark-skinned stranger. “Aren’t we all black 
down that pit?” asks one of the men.
“It’s from the miners in Wales,” Robeson explained, “[that] I first understood the struggle of Negro and white together.”
 Following a deadly explosion, the pits are closed, leaving the villagers
 out of work and struggling to make ends meet. Wanting to help the 
community that welcomed him so generously, David rouses a group of 
activists to march to London in the hope of reopening the mine in time 
to serve the nation at the outbreak of war.
In taking on this role he was fulfilling the promise 
that emerged in his early days as an actor in the West End of London 
where he starred in the production of Show Boat at the Drury Lane 
Theater back in 1928.
It was there that he met a group of 
unemployed miners who had marched to London to draw attention to the 
hardship and suffering endured by thousands of miners and their families
 in South Wales. He was drawn by their singing and began a friendship 
with the Welsh miners that endured for decades. In the next ten years 
he’d donate money to and visit the Talygarn Miners’ Rest Home and would 
sing in various towns including Cardiff, Neath and Swansea – once, in 
Caernarvon, he appeared the day after 266 miners lost their lives in 
nearby Gresford. https://teifidancer-teifidancer.blogspot.com/2016/09/gresford-colliery-disaster.html 
In 1938, he famously sang at the the 
Welsh International Brigades Memorial at Mountain Ash to commemorate the
 33 Welshmen who had died in the Spain civil war, telling the audience 
“I am here because I know that these fellows fought not only for me but 
for the whole world. I feel it is my duty to be here.”
The film Proud Valley may to some seem to be overtly sentimental and about the past, and may be about an industry that has 
all but come to its end in the United Kingdom, but is still 
easy to relate to, so moving and poignant. It is about community, and the spirit of a man who 
fought for the people who welcomed him in with open arms. 
The Proud Valley  remains a fitting tribute to Paul Robeson who is revered as the finest Black actor of the era, who remains endowed with both integrity and honour. As the son of a former slave, he appreciated the capacity of music to liberate the soul from the back-breaking and heart- breaking toils of manual Labour. It was this knowledge that connected him, intuitively and politically with the Welsh miner. He supported them during their greatest struggles and they never forgot him as he faced persecution in McCarthy's America, when he was denied a passport by US authorities and actively campaigned in his support. 
Paul Robeson to me remains a mighty Goliath of a man, s quintessential everyman whose heroic  life continues to inspire the people of Wales and the world, remembered for his commitment to the liberation of people across the globe.
As the Manic Street Preachers insist in ' Let Robeson Sing'; 
A voice: so pure-a vision so clear
I've gotta learn to live like you
Learn to sing like you
Here are links to two earlier posts in the great man,
The film is available to watch here: