The government's own green advisory body, the Sustainable Development Commission, has today called for a major overhaul of the UK's aviation policy and a halt to airport expansion plans.

The study, which was undertaken in conjunction with think tank the Institute for Public Policy Research (IPPR), claimed that the government's support for airport expansion was based on widely disputed environmental and economic data that made it "impossible to weigh up the true benefits and impacts of aviation".

It warned that the government would be leaving itself open to legal challenges if it did not commission a fully independent review of its 2003 aviation white paper, which supported a raft of new runways at Heathrow, Stansted and other airports.

The report recommends that plans for a third runway at Heathrow should be put on hold and that future decisions on aviation policy should not preempt upcoming international policy decisions currently being negotiated by the EU and UN. It also calls for the creation of a special commission to compile an "updated evidence base on the economic, social and environmental benefits and costs of UK aviation" that seeks to deliver maximum consensus between different stakeholder groups.

"Good policy-making needs to be based on evidence that is widely agreed to be sound, which is not the case when it comes to aviation policy," warned IPPR associate director Simon Retallack. "Before any major new decisions are taken on airports, it is vital that the evidence is looked at again through an independent and widely supported process."

The government rejected the reports findings, insisting that a further three year debate on Heathrow expansion "is not a serious option". A spokeswoman for the Department for Transport said that the government fundamentally disagreed with the report's conclusions. "It is wrong to claim that there is a consensus that the evidence base is flawed and, as the report admits, the most recently published background data on Heathrow was not even discussed," she observed.

The report was released on the same day as the government was accused of using outdated oil prices on which to base its road policy decisions.

According to Guardian reports decisions on road building and pay-as-you-drive schemes are being based on the assumption that oil prices will reach no more than $70 a barrel between now and 2020, despite a recent spike in prices that has seen oil approach $130 a barrel.

The figures were revealed in response to a parliamentary question from Liberal Democrat shadow transport secretary Norman Baker, who labelled the projections "absurd" and insisted that "nobody outside the government" would regard them as accurate.

However, a spokesman for the Department for Transport insisted that it was using higher projections to inform its decisions. "To ensure robust estimates are produced, we also factor potential high oil prices into our modeling," he said. "For this we use BERR's higher projections for oil prices. The current higher forecast for 2010 is $107 a barrel and for 2015 it is $150 a barrel, in 2007 prices."