On Wednesday, however, Chief Justice Wayne Martin deemed the Roe 8 approval - as well as the ensuing approval from Environment Minister Albert Jacob - invalid. A protest against the Perth Freight Link at parliament in November. Credit:Mark McGowan MP "The EPA took no account of its own published policies at the time it made its decision and provided its report to the minister," Chief Justice Martin said. "The court also concluded that the EPA was legally obliged to take account of the policy."

Joyous scenes erupted in court and quickly spilled outside. Save Beeliar Wetlands spokeswoman Kate Kelly said the decision meant the homes of endangered black cockatoo species would be preserved. "Over 30 years or longer, people have been trying to save this very critical asset," Ms Kelly told reporters. The ruling means at the very least a long delay for the project, for which drilling had already begun in the wetlands. Opposition environment spokesman Chris Tallentire told reporters he believed it would not go ahead.

Shadow parliamentary secretary Allanah MacTiernan released a statement saying the ruling should be the "final nail in the coffin", and called on Mr Turnbull to abandon the federal funds commitment and put the money towards rail. "Now Western Australia faces another long delay in receiving further federal infrastructure dollars, with the approvals process sent back to the drawing board and no money set to flow ... surely no more than a distant dream," she said. But Premier Colin Barnett reaffirmed his commitment to the project no matter how significant the delay, the ABC reported. "It means that the hundreds of jobs will be delayed and indeed the danger in terms of traffic in the area will continue longer than I would have hoped," he told the ABC. "As I see the ruling, the actual project is okay. It's about [environmental] offsets."

An EPA spokeswoman said the board would need to take its time to fully consider the findings and it would be inappropriate to make any further comment at this stage. Similarly, a spokeswoman for Minister Jacob said he would consider the judgement and take advice. Hundreds have protested the 5 kilometre extension of the highway from Kwinana Freeway, Jandakot, to Stock Road, Coolbellup, through the North and Bibra lakes, green-lit by the EPA in 2013 and then finally by the Minister this July. Labor, the Greens and the Conservation Council of WA have all opposed Roe 8 and questioned various approvals granted. Labor in September called for Mr Turnbull to scrap the Commonwealth funding former PM Tony Abbott had pledged to the $1.76 billion Perth Freight Link, planned to run from the outer suburbs to Fremantle Port.