Years ago, the Australian Taxation Office was famous for having the best parties in Canberra. Friday nights at the Rex Hotel were a regular venue where then-tax commissioner Bill O’Reilly held sway, typically surrounded by smart-suited, young ATO men, eager to hear directly from their revered boss.

It was very much an insider group but dotted with occasional ministers, advisers and secretaries lucky enough to secure an invitation. For decades, the ATO had been a closed shop, seen, along with customs, as very much a “Catholic” organisation – a reference to the time when its head office in Melbourne was dominated by workers from that city’s powerful Catholic school alumni.