Even if I didn't suffer a rictus of the jaw, it would certainly leave the bitter taste of gall. No, I had to avoid this humiliating experience. I would have to go undercover and disguise myself as a local.
I have always rather admired people who go about in disguise. In his wonderful history of the "Great Game", Peter Hopkirk describes how, in the late 19th Century, young British officers and their Russian opposite numbers would assume local disguises before setting off on intelligence missions in the wilds of Asia. Sometimes they came back and sometimes they did not but it was a world of danger, excitement and adventure.
Can there have been a better evening that the one spent by Francis Younghusband, who famously accepted a dinner invitation from his Russian equivalent, who was camped further down the Yarkand Valley? Both superb linguists, it is said that they drank late into the night and I am willing to bet that, enemies though they were, what they said about their respective colleagues was indiscreet in the extreme.
I do not claim to come up to those standards but I do have a little experience about what not to do.
For example, it is better not to start in a tourist shop. An attempt to pass as an Austrian by donning lederhosen and a magnificent waistcoat with a stag across the chest proved unconvincing - even though the chap who sold it to me assured me it was very traditional.
Then if you do buy something local, you should find out who wears it. You do not want to be thrown out of the local temple because your outfit turns out to be the uniform of the city's ladies of the night - especially if you happen to be a man.
Sometimes, too, you can go too far. I once asked an Islington theatrical outfitter if he could fix me up with something typically German so that I would be inconspicuous on a visit to Cologne.
He told me that he only did two types of German. The first wore a spiked helmet, which seemed to me to be a little out of date; the other was a Lutheran priest.
In retrospect, I doubt if he knew much more about Lutheran priests than I did, but theatrical outfitters do not lack confidence, so a week later I stood on the banks of the Rhine sporting a false beard, pebble glasses, a black gown and a large silver cross, all topped off with a flat black hat.
I had learned a sentence of German, too, to complete the effect. I don't think it fooled the locals much, although one of them did such a double take that he nearly rode his bicycle into the river.
My mother, whom I had gone to meet, was completely taken in, however, and I'll swear I heard the words: "Look, it's an undertaker" in rather a shrill American accent.
So how to pass as local on the streets of Wanganui? Fashions are not so different in England that it is necessary to change my clothes. Keep silent? - well, that is obvious.
What about facial expression, then? I need to get rid of the depressed look of an English cricket fan and pin a smile there instead. It looks as if I will get that rictus after all.
Before retiring, John Watson was a partner in an international law firm. He now lives in Islington, London, and is currently on holiday in Wanganui.
