Re: I think not
"And what's the effect of IR35 on the cost of the deliverables?"
As-good-as nothing.
For one contractors are, with a few exceptions in the secure sector, never a significant proportion of the cost of delivery. If they are then CabO get very, very annoyed because of the delivery risk of having so many freelancers who can fuck off at a moment's notice without penalty.
Second, this has manifested in most departments as a changing of hats. Three scenarios dominate:
1) Nothing has happened. This is most common and typical of the big departments. Contractors were indirectly acquired as subs through one of the big SIs as part of a delivery or framework contract (i.e. not T&M). This isolated the department from the new compliance rules so nothing changed for the department or ultimate contractor.
2) The contractors have shifted to move under a framework agreement or have changed their terms to be delivery-centric. You're only at risk of IR35 if you're working on indefinite T&M terms. Redefine your contracts to align to project deliverables, and audit your compliance with the terms and the IR35 compliance requirement is satisfied.
3) The freelancers who weren't under deliverable terms and didn't want to move under those terms have left and been replaced by those who are more than happy to take their place.
Direct, long-term contracting has been extremely rare in the public sector for over a decade now. There is always an intermediate entity, even if it's only Crapita processing your timesheet. The changes to IR35 compliance rules were, in reality, pretty minor and didn't apply to many people.
Let's look at this in the cold light of day. Cracking down on freelancers is, on balance, probably not a good thing, but this is a "survey" published by a contractor services organisation, quoting a clutch of anonymous, pissed off contractors annoyed by a measure targeting contractors and published on a tabloid website read by those same contractors. Hardly an unbiased report. Back in the real world, IR35-derived resourcing risks don't make it onto any of the Infrastructure and Projects Authority's risk registers, and haven't even been a topic of discussion in the departments I work with.