The high page count stems from Optus and Telstra unnecessarily itemising each individual piece of web data downloaded using the phone, instead of having a single usage figure for each day. One customer estimated that if he had used his full 850MB allowance his bill would have been more than 80 pages.

While focusing on alternative energy production, Senator Obama has veered in recent days toward increasing access to fossil fuels, both in seeking to tap the strategic oil reserve and in softening his opposition to offshore oil drilling.

Wentworth Group scientist Peter Cosier labelled as “insignificant” the water returned to the Murray River so far this year and said the full $3 billion allocated to the federal government buyback over the next decade should be spent in one massive purchase.

Senator McCain, the presumptive Republican nominee, had earlier dropped his own opposition to offshore drilling, saying that soaring gas prices demanded new approaches. A bipartisan proposal currently before Congress would include more subsidies for alternative energy sources as well as authorization for limited offshore drilling.

Senator Obama, the presumptive Democratic nominee, has until now opposed any expansion of lands for offshore drilling. But at a news conference in Florida, he noted that there had been “very constructive” talks between Senate Republicans and Democrats on the issue in recent days.

In May, the multibillion-dollar oil giant Exxon Mobil acknowledged it had been funding groups that had fuelled a global campaign to deny climate change. Exxon’s decision to cease its funding of these groups came after a shareholder revolt by members of the Rockefeller family and big superannuation funds, which aimed to get the company to take climate change more seriously.