In a candid confidential memo to Creative Scotland, more than 60 film producers, including the makers of Sunshine on Leith, Under the Skin, Perfect Sense and Rob Roy, predict the demise of a faltering film sector.
They say: "While on the surface Scottish films continue to punch above their weight ... the real picture is extremely bleak.
"In other countries, film producers with the right support are able to make a living out of film ... in Scotland, however, the vast majority of film production companies and producers are in financial crisis. Lack of funds and support is killing the industry."
The lack of attention paid to the industry by both Creative Scotland, which has £3 million in lottery funds a year for film, and Scottish Enterprise mean they have been negligent towards the sector, it is claimed.
The letter was written and submitted by the Independent Producers Scotland group (IPS), which was recently told there was no extra money in the budget of Culture Secretary Fiona Hyslop to boost the film industry.
Recent weeks have seen a series of Scottish film successes, including high-profile premieres of Sunshine on Leith, a musical drama based on the songs of The Proclaimers, and Filth, which stars James McAvoy in the adaptation of Irvine Welsh's novel, as well as screenings at the prestigious Toronto International Film Festival of Scottish-made Under The Skin, starring Scarlett Johansson, and Scottish director David Mackenzie's Starred Up.
However, in the letter to Creative Scotland sent on August 6, which received a reply only this week, the producers say the situation for Scottish film will be grave unless the Government immediately implements a "long-term growth strategy for the industry".
In the letter, sent to Caroline Parkinson, director of Creative Development, the producers say: "Film is an art form and a brutal business but this is not recognised in Scotland.
"Film needs to be supported by policy makers in both the economic and cultural sector ... the fact that it is not is having a devastating effect on the sector."
The letter is signed by the leading film producers in Scotland, including Arabella Croft, producer of Sunshine on Leith; Gillian Berrie, producer of Under The Skin and Red Road; Eddie Dick of Makar Productions, who made Outpost and After Dark; Nick Higgins, who made We Are Northern Lights; and Claire Mundell of Synchronicity Films, makers of Not Another Happy Ending.
The letter compares the £3m available from Creative Scotland to the £52m screen investments in Denmark, £36m in Sweden, £13m in Northern Ireland and £21m in Norway.
It asks for the establishment of a clear film department in Creative Scotland, funding increases to at least £5m annually for development and £10m for productions, and the removal of a £300,000 cap on spending on individual films.
It also criticises Scottish Enterprise, saying that it has not "demonstrated any belief that our local film industry can contribute much" to the economy.
The letter adds: "While there is clear evidence that investment into film can reap healthy returns, it is negligent for Scottish Enterprise and Creative Scotland not to pay more attention to the sector."
Last night Janet Archer, chief executive of Creative Scotland, said: "The points made regarding the funding support for film development and production are clearly of significant value to Creative Scotland and to the Film Review.
"We have shared the letter within our team and will also share it with Scottish Government colleagues and will collectively discuss how to address the concerns raised.
"At this stage it is not possible to answer each of the points made as we await the outcome of the Film Review, which will be submitted in draft to us shortly, and be published in January 2014."