Outgoing Woolworths boss Brad Banducci was threatened with six months in jail for contempt of the Senate after he refused to directly answer questions about a profit metric, in a fiery Senate hearing that went off the rails on Tuesday.

Mr Banducci declined to confirm if the supermarket giant’s return on equity was 26 per cent, twice that of the big banks but similar to miners, saying it was not the best way to measure the profits of supermarkets. The retailers, like the big miners, argue that other metrics such as return on capital are a better indicator of how profitable the business is.