If more proof were needed that the Business Council of Australia has abandoned advocacy in the national interest, today’s breathtaking defence of tax avoidance by chief executive Jennifer Westacott delivers it in spades. It’s now clear the BCA operates purely in the interests of big business.

This morning the Australian Financial Review’s star investigative reporter Neil Chenoweth, working on a 28,000-page cache of documents leaked to the International Centre for Investigative Journalism, has sensationally exposed Australian businesses that use Luxembourg as a tax haven, including the Future Fund, AMP, Lend Lease and Macquarie Group and others. Tax commissioner Chris Jordan has vowed to investigate.

There is no more important agenda item at next week’s meeting of G20 leaders in Brisbane than measures to tackle so-called base erosion and profit shifting, or the avoidance of tax by multinational companies who are threatening the revenue of governments worldwide.

But today the BCA and Westacott are pushing back on any G20 tax crackdown lest it undermine “investment, innovation and entrepeneurialism”.

“We should acknowledge the contribution made by business,” urges Westacott, “more than $70 billion of company tax is expected to be collected this year”.

The BCA has already walked away from a rational contribution to climate policy and plumped for an industry policy that would take Australia back to the bad old days of picking winners.

Such narrow advocacy of a big business agenda is bad policy — and ultimately bad politics.