But there's no problem when the PIL are Sir Argus and Lady Cutpurse. If fond of the latter, as I have been of both my MILs, I have become familiar and called them ''Lady C'' or whatever.

Some of their other children-in-law addressed them as mum or dad. Or, mostly, not called them anything at all, other than adopting terms such as grandma in a third-person sort of way if there were grandchildren about.

In these much more informal days, a good many people - such as my own disrespectful sons-out-law - refer to me and any of their parents-in-law by their first names. Indeed some allow their own children to call them by their first names. Likewise all of my siblings-in-law always called my parents by their first names, and would have been expected to. My mother would have cringed had a son-in-law called her mum.

But it wasn't always so, even in relaxed households, and while my mother was not nearly as terrified of her FIL as my father was of his MIL, I do not think she ever called him Will. Or anything, come to think of it. My father called his FIL Ned, if only because Ned had any number of unassuming ways of being the sun in a solar system with nine planet families (plus a nun) circulating outside. But he did not call his MIL Norma, or anything that I can recall.

Avoiding calling the in-laws anything has a long lineage. In many tribal and traditional societies, one never speaks to, or even looks at, one's MIL or with any other women of the same classificatory relationship. If one must speak to them, one speaks to a third party, saying, for example, to one's wife when MIL is in the room and can hear: ''I wish you would tell your mother not to snore so much.''

MIL might reply, without third-party intervention but in a manner directed to her daughter: ''Snore, eh. What about telling him to put the toilet seat up?''

The old Emily Post guides on manners used to deal with the problem of what to call PILs by suggesting brightly that one ask them what they prefer. This is fraught with danger and not recommended by me, if only because of the tendency to be bound by the answer, even if it is cringe-making.

It can, of course, also be awkward if one adopts an over-familiar form of address which they do not like, which is a good reason, in my opinion, for avoiding first names and nicknames, at least, until the ground is, as it were clear.

In many families, where partners plighted their troth at pre-school or one has been dragged home in a crowd of people and introduced to (at that stage) unknowing people in a job lot, there should be no awkwardness. But sometimes, first encounters with future PILs are fraught with already-intimidating terrors and able to be aggravated by breezy overfamiliarity.

My second duchess, for example, neglected to inform me that her father - a formidable lawyer, conservative and knight of the realm - was a former Sunday school superintendent, well-known for his absolute abhorrence of drinking, smoking and gambling, and not famously keen on reptiles of the press. When I first encountered him, I was smoking a cigarette. Soon after, the ever-graceful Lady B asked me whether I would like something to drink on such a hot day, and I responded that a beer would be fine, thank you.

Perhaps because of such matters, I never did receive a telephone call at which the FIL introduced himself by name (perhaps the best clue to what he would have preferred to be called), but when we did speak, I called him Sir X. As I had done with the father of the first duchess.

Both men were called by their first names, without reference to the knighthood, by their old mates, as were their wives. But even old mates, introducing them to strangers, would do so formally.

Likewise with most of the knights with whom Canberra was once graced. Until the 1980s, knights, and even the occasional dame, were common enough (if that is the right word) in Canberra. Most came from the ranks of the judiciary and the public service, with the odd politician, media baron or philanthropist.

All of them - particularly those who had once trumpeted their egalitarian outlooks - gave every sign of being absolutely delighted with the status and prestige of being raised above the herd, although a good many would privately claim that it meant nothing to them, but gave their wives so much pleasure that they had been unable to resist when the award was offered.

It was perfectly true that most wives did relish the status - and occasionally the opportunity to put some upstart in her place. But I was never convinced that their husbands had made a great sacrifice on this account.

High Court judges received an offer of a knighthood as a matter of course - merit having nothing to do with it. One could refuse, as did, say, Lionel Murphy, but very few felt able to. These days, High Court judges are automatically appointed Companions of the Order of Australia. The citation will speak of their services to the law, but it is actually an incident of the job, and quite a few have won it without ever having performed any sort of public service, apart from being very good, and extremely well-remunerated, lawyers.

The drawback of the idea that knighthoods should be restored so as to avoid any embarrassment or awkwardness is that everyone of a certain age, or at least with marriageable children of a certain age, would have to be made a knight or a dame.

That would be raising respect for one's elder to a new level, though it is, I guess, a sacrifice that would be worth it.

Restricting the honour only to the parents of married children would, I think, create insuperable issues. Married to whom, or what, for example? What if the parents themselves were not married, or to each other? If the wives of a knight are Lady X (though the husbands of dames are Mr X), what of the same-sex partners of either? Sooner or later Tony Abbott would have to ask Cardinal Sir George Pell.

Perhaps the issue has become anachronistic. One of my aunts, observing the advanced pregnancy of a great-niece, asked about plans for a marriage. ''Oh, we're not getting married,'' she was told. ''Marriage is for gays.''