Still on the Banksy theme, a number of other extraordinary factors have emerged after the shredding incident at Sotheby’s. Firstly, footage of the drama unfolding released on Banksy’s own website shows that he must have had several representatives in the room as the film is taken from various positions at the same time.

Bizarrely, to my mind, some art experts argue that the ‘performance art’ episode now attached to the piece has possibly doubled its value, despite the fact that it is now largely cut into strips, which frankly doesn’t say much about why some people treasure art.

Perhaps even more bizarrely, it now turns out that at least one other owner of a Banksy work has taken a Stanley knife to it in an attempt to replicate the stunt and thereby double the value of the piece… only to discover that it is one thing for Banksy to do this, quite another for them to give it a go. In their case the five-figure work is now worthless.

As I have advised before, values are subjective and can prove unpredictable, especially under circumstances like these. In normal times, around half a dozen factors help determine prices at auction, but when the extraordinary happens all bets are off.

Meanwhile Frieze, the art fair conglomerate on show in London that normally expects to dominate the headlines at this time of year has had to play second fiddle to this affair – not something it has experienced before.

One of the most extraordinary things I have heard took place at Sotheby’s in London on October 5 after a picture by the mysterious Street artist Banksy sold at auction for £1m.

After the hammer fell to the successful buyer on Girl with a Balloon, a noise started and the audience watched as a shredder within the picture’s frame proceeded to destroy it. To some people this was another inspired and sensational move by one of the art world’s bad boys as he thumbed his nose at the establishment. All very entertaining in its own way, I suppose.

However, it’s worth remembering that a lot of people would have put a great deal of time, effort and money into preparing the picture for auction, publicising it, and attracting bidders. What about them? Is Banksy going to compensate them and the auction house for lost fees? What about the buyer, who thought enough of the artist to make a £1m bid? Should they be treated with contempt in this way? Or is Banksy the only one allowed to make money out of his art, regardless of all the help and support he has along the way from others? If he doesn’t like his art being exploited financially, I suppose the simply answer would be not to sell it in the first place.

As a piece of theatre, I’m sure the shredding of a £1m artwork at the point of sale makes for a memorable occasion, but as a self-indulgent act at the expense of others, I’m not sure how admirable it is.

The episode of the Cottingley Fairies did nothing to enhance the reputation of Sir Arthur Conan Doyle, who was taken in by the hoax along with many others, and widely ridiculed as a result.

It all started in 1917 when cousins Elsie Wright, aged 17, and Frances Griffiths, aged nine, took photos of themselves in their garden with what appeared to be dancing fairies and a tiny gnome. In fact they were cleverly crafted coloured cut outs supported by hatpins, but enough people were taken in by the trick for serious discussions about the existence of fairies to arise over a number of years. Conan Doyle went into print more than once on the subject. Around 20 years ago a film of the story was released.

Now the two images are coming up for auction with hopes of £2000.

It’s astonishing a century on that so many people could have been taken in by the hoax, but I believe Conan Doyle should be seen in a more sympathetic light. He had already lost a wife and son and developed a serious interest in spiritualism over a period of 30 years. The thought of life after death and the possibility of being able to contact lost loved ones must have been highly appealing and a great comfort to him.

The Cottingley Fairies episode would have added to his fascination and research and he was keener on being remembered for this side of his life than for his fiction.

It used to be all about the Three Ds – Death, Divorce and Debt – when it came to reasons for consigning to auction. Now you can add Downsizing and De-cluttering as modern tastes moved towards minimalism in the home and older couples cashed in their property portfolios once the children had flown the nest.

I was reminded of all of these this week as news emerged of a sale that has arisen as a result of Debt. Adding another D – this time for Disaster – the theme of the sale will be the Titanic, whose sinking was a unique event in history that continues to fascinate and horrify in equal measure owing to both the sheer scale of the loss of innocent life and its symbolism. Few catastrophes (the 2004 Boxing Day tsunami was another) better illustrate the lasting truth that no matter how developed and sophisticated we become as a species, humans are only ever a small step away from the unstoppable caprice of nature.

In this case a company specialising in exhibiting Titanic memorabilia has filed for bankruptcy, leaving all the exhibits up fro grabs. When you consider that the violin played by the bandleader as the ship sank sold last year for $1.7 million (it’s not part of this sale) the attraction of Titanic items becomes obvious.

However, putting all the pieces on the market at once risks deflating values, so it will be interesting to see how the administrators handle the auction.