The government today unveils its replacement for PFI as a way of funding future infrastructure projects such as a Forth crossing.

But Labour, having received a leaked copy of today's planned announcement, condemned the plans as unworkable and poorly thought through, claiming this was the reason they were being sneaked out on the last day of the parliamentary term before Christmas.

In answer to a parliamentary question today from backbencher Alex Neil, the Finance Secretary John Swinney will announce details of proposals for a Scottish Futures Trust and open a consultation process on this.

It marks a shift from the Private Finance Initiative under the Conservatives, to the broadly similar Public Private Partnership under Labour, and now to the Scottish Futures Trust (SFT) under the SNP.

Under the previous schemes private companies got together to form consortia to bid for school or hospital projects.

These then built, owned and operated the facilities for terms of up to 30 years, amassing big profits along the way.

Now a holding company would be formed as the SFT.

Beneath that would be a management board which would raise money from banks, private investors or through bond issues to fund future infrastructure projects "on non-profit distributing principles".

But Labour claims that if the holding company board members are publicly appointed then the SFT will not be an arms-length private body, and as a result the benefits of private finance would disappear.

Labour's shadow finance secretary Andy Kerr said: "This is an embarrassing climbdown from the SNP, given it has taken them until the last day of the session to release their alternative to PPP/PFI. Their flimsy consultation document is a major retreat from their original plans and reveals that their much-vaunted alternative to PFI is at best simply re-badged PFI."

Today's consultation document states: "The Scottish Government considers the proposals in this paper to be a sound basis for establishing a new infrastructure investment vehicle which will replace the stark choice between conventional and PFI methodology currently available."

But it admits: "Some aspects of the proposals for SFT set out in this paper give rise to questions."