Liberal senator Arthur Sinodinos suffered a serious outbreak of forgetfulness this week when subjected to waterboarding at the Independent Commission Against Corruption hearing into Australian Water Holdings and its charging of exorbitant expenses to Sydney Water while he was a director.

Senator Sinodinos' testimony was littered with the tell-no-tales phrase that goes with loss of memory: ''I don't recall.'' It is a malady that affects many of the great and good when giving evidence to legal or government inquiries.

Only the week before last, Cardinal George Pell had a slight case at the royal commission on institutional sex abuse, forgetting details of financial transactions to compensate priests' victims.

And 10 years before Monica Lewinsky's dress took him to the cleaners, former US president Bill Clinton could not recall 267 times in a 1988 deposition in the Paula Jones sexual harassment case.

There was a time Australians hardly ever saw their leaders suffer in the witness stand. But the phrase ''I can't recall'' came ashore courtesy of communist inquiries in the US, and became all the rage. Forgetful billionaire Alan Bond fronted court in 1994 with a mind gone blank, thanks to a succession of minor strokes. A year later, Bond's fellow sandgroper, former premier Carmen Lawrence was in a similar lost state when giving evidence at a royal commission on the suicide of Perth lawyer Penny Easton.

And who could forget the collective amnesia of Lachlan Murdoch and James Packer when they were asked in court to explain losing $1 billion of their fathers' money on their joint venture One.Tel.

They all proved to be as good as their words and lived to forget another day.