Barry O'Farrell did what he could to minimise the political impact of his maiden visit to the Independent Commission Against Corruption.

There was one thing, however, he couldn't control: his lack of a plausible explanation as to how it was he did not receive a $3000 bottle of 1959 Penfolds Grange his acquaintance Nick Di Girolamo sent him as a gift just after he won the March 2011 election.

ICAC heard evidence that the precious bottle was sent by courier to O'Farrell's home. Under oath Di Girolamo said O'Farrell even called him to thank him for it. O'Farrell insists, also under oath, he never received it. Who to believe? The Premier's problem is that we are asked to accept that the bottle was stolen or otherwise disappeared from outside his home in Roseville, which he describes as a ''friendly'' neighbourhood. That alone stretches the bounds of credibility.

His inability to recall the contents of a 30-second phone call to Di Girolamo the evening the bottle was purchased compounds the suspicion we are not getting the full story. The episode has exposed O'Farrell's lack of candour about his relationship with Di Girolamo. Rather than barely knowing each other as he has previously implied, it has emerged the pair had each other's private mobile numbers and were in frequent contact.

Di Girolamo says they talked perhaps once a fortnight; O'Farrell says it was more like once a month.

For many, the pertinent question might therefore become: if we cannot trust the Premier to be up front about his relationship with Di Girolamo - a Liberal Party fund-raiser and former lobbyist - why should we believe him about a potentially embarrassing gift?

O'Farrell is well aware that when you are summoned to ICAC, 90 per cent of the battle is maintaining a veneer of honesty by being forthright and thorough with your answers. ''I don't know'' - a version of the more notorious ''I don't recall'' - achieves precisely the opposite.

A previous version of this story said Mr O'Farrell may have entered the hearing room via the basement. He actually entered through the front door