With debate raging over what should replace the UK's influential tax deferrals, only two things are certain.

Firstly, many in the industry support preserving a status quo that last year saw investors shelter $2.7bn (£1.6 bn) through sale and leaseback schemes and, to a far smaller extent, riskier production schemes.

Secondly, change is on the cards, with both the UK Film Council and research body British Screen Advisory Council (BSAC) submitting proposals to focus the tax deferrals on distribution as well as production.

BSAC's key recommended change to the Section 48 tax deferrals - which is aimed at British films budgeted under $25m (£15m) - is understood to be that a film must have a distributor on board. The proposal is said to mirror the existing mechanism, but spreads out benefit to distributors as well as producers, although the producer ultimately accrues all the benefit.

The UK Film Council's proposal to the Select Committee, the think tank currently examining how Government should support the film industry, compares a producer-led UK industry to the distribution-led US studios.

"Any new relief should be designed to enhance the competitiveness of the indigenous UK production sector AND address the weak linkage between film production and domestic and international distributors," the council's preliminary report states. "Fiscal policy should offer a more effective way of encouraging both international and UK distributors to engage more actively with the UK production sector."

With both proposals submitted to the committee confidentially, and the government unlikely to reach a decision until late next year, players across the industry say that the current uncertainty is turning the UK tax haven into a nightmare.

"The worst thing would be not knowing anything for the next 18 months," says Keith Evans of tax financier Baker Street. "We don't know how to handle this. There is no cohesive debate. "

"It's impossible to create something meaningful using the tax breaks when they constantly have an axe hanging over them," adds Gary Smith, head of Winchester Entertainment.

Some seem to be banking on distribution being a tax-friendly business in the near future. Franchise Pictures is shopping for a distributor to oversee its nascent UK releasing partnership with tax fund Invicta. Another US outfit, Bauer Martinez, which is already busily mining UK tax funding, has teamed with UK distribution veteran Martin Myers.

But some are angry that the Film Council has instigated such change and that the industry needs continuity. At the Commons Select committee, former Civilian Content chairman David Elstein argued that abuses have been stamped out and the breaks are only now starting to work. Changing the system now may merely unsettle investors and trigger a new wave of abuses.

Some structural change is already evident, with distributors such as Redbus stepping up production. Meanwhile, distribution or international sales are already key in many cases. Companies such as Baker Street say they never finance a film without sales attached, while producers use tax money to bring distributors on board at lower prices.

But not everyone is so convinced. While some tax financiers are more stringent, many have produced slates of films that have never found UK distribution. "I don't think those guys are as rigorous about films as I am," says David Kosse, head of distributor Momentum Pictures.

Some producers argue that, as Film Council chair Alan Parker's asserted last year, the breaks have failed to create a sustainable industry in the sense of capitalising companies. "It helps me make films; it doesn't help my business," says producer Richard Holmes.

One last thing is also certain: almost no one wants support to disappear entirely. As the Inland Revenue's David Easton notes, that is very much a possibility: "As the law stands, if there is no further action, that is what will happen," he says.

That would be a disaster, BSAC argues. Dramatically, the body's proposal says that creating a sustainable industry, the stated goal of the Film Council, is impossible, if that means an industry without support. "There is no shame in saying that there have to be incentives," says Fiona Clarke-Hackston. "It is just a question of how you do it."