UK film TAX question (not Café material)

[Eats_Crayons]

This is more of a tax/investment type question rather than an "arts" question...

Could someone explain this "tax loophole" a bit?

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.

I don't get it. How do they "pull out" of an investment like that? And is it something that is uniquely exploited my film investors or is it a more widespread practice with other forms of investments as well?

I am speculating that it's sort of the following:

Multi-millionnaire rich dude/dudette invests $1 million in a movie.

Before movie makes profit, dude/dudette severs all connections to the film.

This results in a $1 million dollar loss. (Even though film goes on to earn lots and lots).

The $1 million loss offsets some tax stuff -- like brings them into a different bracket or something.

Does the loss offset something? How does the multi-millionnaire due/dudette benefit from this? How the heck does the whole "pulling out" process work? Do they somehow "uninvest" the funds? How? Or is it like I speculate above and they lose the money they invest?