Aspiring screenplay writers have been offered a chance to launch their careers by leading director Sir Ridley Scott and renowned actor Idris Elba.

The pair have both launched writing competitions in an attempt to unearth hidden British talent in a ferociously competitive industry.

The director, whose films include Alien, Blade Runner and Gladiator, is hoping to develop at least one successful film project through his Launch Pad Manuscript Competition. “Without [writers], I would not be able to do my job,” said Scott. “So, to be able to provide a new and innovative way for them to get their work out in the world is truly exciting.”

Through his company, Green Door Pictures, Elba, whose acclaimed performances include the crime series Luther and The Wire, has launched the Write To Green Light Competition, with the aim of developing a major television series from the winning entry.

The competitions reflect a recognition of the huge challenges faced by scriptwriters, who often struggle to obtain even a cursory reading of their work. In the past, desperation drove one hopeful writer to leave his manuscript under the windscreen wiper of the car of one of Scott’s executives.

Mike Pruss, the senior vice-president of production for Scott Free, which will run the Launch Pad competition, recalled returning from a lunch one day to find a package with such a “sweet note” that he simply had to read the manuscript. “I don’t know how he knew it was my car. I did email back, ‘thank you for your time’. We probably get thousands of screenplays and manuscripts a year. It’s an extraordinary amount,” he said.

The problem was “over-saturation”, he said. “There are so many more people doing it now because everyone feels they have a great story to tell … Like any business, the product may be good, but it may not be right for the company.”

Almost half of the Oscars’ best picture nominations of the past 10 years began as books, with fiction such as the Harry Potter series and Fifty Shades of Grey achieving phenomenal success on screen. Winning writers will also be signed up with management company Energy Entertainment and published by Inkshares.

The competition, which is open to new and established writers, asks for submissions of up to 50 pages.

Pruss said that The Martian, starring Matt Damon, reflected Scott Free’s track record in taking a chance on new writers and new platforms. Originally self-published, Andy Weir’s book inspired the screen adaptation, which became one of the biggest films of 2015, nominated for seven Oscars.

Elba’s productions, through Green Door Pictures, include A Hundred Streets, in which he starred with Gemma Arterton. He is collaborating on his competition with Lionsgate UK & Europe, a leading producer and distributor.

The brief is for major television dramas with “culturally British stories”. Three finalists will have a 15-minute extract performed by major actors at a live public event later this year, when a panel of key industry figures will make their final decision. The audience will include top broadcasters, commissioners, producers, directors and talent management. The winning script will be optioned and go into production in 2017 or 2018. If there’s a part that Elba likes, he could play it.

Zygi Kamasa, chief executive of Lionsgate UK & Europe, said that the competition reflects the company’s “big drive” to expand its reach into UK television. Lionsgate has acquired a stellar reputation in the US, with acclaimed shows such as Orange is the New Black, set in a women’s prison, and Mad Men, about advertising executives.

He and Elba were addressing “a huge shortage of undiscovered television writing talent”, he said. “Where’s the Mad Men in the UK. Where’s our really great quality writing?”

Part of the problem, he added, is that television drama writers have only four UK broadcasters to approach – the BBC, ITV, Channel 4 and Sky: “In America, there’s over 40 broadcasters and cable channels making shows. Admittedly, the US is bigger, but still 40 compared with four is really disproportionate. If you’re an undiscovered talent or a talented existing writer and one of those four buyers says ‘no’, you’re stuck, you’ve hit a brick wall. You might have this terrific script and it just doesn’t happen to be right for commissioners at that time.

“We think we can discover perhaps those hidden gems among really talented British writers.”