After first launching its review in February, the Trust today approved the Canvas proposal, but with conditions attached related to industry engagement and costs.
However, Sky has been highly critical of the project on grounds of a perceived bias towards public service broadcasters and the potential use of public money to distort the nascent IPTV market.
In response to the Trust's ruling, Sky's group director of corporate affairs Graham McWilliam said that the BBC's involvement remains the "key concern" about Canvas.
McWilliam claimed that there is simply no pressing need for public money to be used in replicating what will soon be produced in the commercial IPTV marketplace.
He instead called on the BBC to focus on producing high-quality programmes and then making them widely available across the emerging TV platforms.
"Internet-based TV is already developing fast and, even without Canvas, the industry is working on shared standards to help it grow even further. There is no need for public money to be spent on replicating what's set to be delivered through commercial investment," McWilliam said.
"In the longer term, consumers will not benefit if the BBC's role in Canvas prevents other innovative services from emerging, as the Trust acknowledges it will. The BBC Trust should have concluded that the licence fee would be better spent on making programmes and distributing them without discrimination across all platforms.
"Yet again, this is nothing short of BBC mission creep and anyone with an interest in the long-term health of the commercial media industry should be very concerned."
Despite the Trust's approval, the Canvas partners will have to ensure that the resulting platform is fully opened up to other service providers under fair and reasonable terms. The Trust will also retain overriding power of approval should the project's budget increase by over 20% in any one year.
However, Sky will most likely reaffirm its concerns during the Trust's final consultation, which runs until February 2, 2010.