- Tulip Fever, starring Jude Law, was to start filming in April - but is on hold after the government closed a tax loophole it said was being abused.
And The Libertine, with Johnny Depp - due to start filming on Monday - is also among 40 films in jeopardy.
The industry is hoping the government will agree to keep the loophole open for movies that are already under way.
The Inland Revenue says investors "exploited" the loophole by putting money into a film but pulling out before it reached cinemas - and avoiding paying tax on their investment. [BBC]
Buddy, if it's there, it's going to be exploited.
- The film industry wants the government to keep it open for current productions to save them from collapse.
Producers had hoped to get a decision from the Inland Revenue on Thursday - but are now waiting for an announcement on Friday.
"As time drags on, it's becoming more and more urgent," according to Amy Seely of the British Screen Advisory Council.
"I believe some production companies are already laying off staff, which is a disaster. It's the smaller companies that are in particular trouble."
There have been dire warnings that the closure of the loophole would turn Britain into "a no-go area for film-makers" - reversing a current boom in film production.
Last year saw an 85% rise in overseas film spending in the UK.
I am sure the intent is not to shut down the film industry - a pretty good demonstration of the law of unintended consequences.
More details from the BBC:
- What is this tax loophole?
Complicated. The "sideways loss relief" is intended to help people who risk their own money by running businesses in partnership with others - but end up making a genuine loss. They can then claim tax relief to soften the blow.