The answer is when you spot the newspaper story most likely to be a jape only to find out it it true.

There is a TV series based on this premise called The Bubble. Three guests of with varying degrees of celebrity (yes, I haven’t heard of some of them) are put in a house together, cut off from all news sources.

After three days they exit, blinking into the daylight and are shown news reports. They then have to decide which are real and which are made up. In essence it is the same as April Fool only it finished last week, in March.

So what madcap tale was it that caught my attention on All Fools Day? It was the one about the publication of Gordon Brown’s speeches, a compilation enticingly titled The Change We Choose: Speeches 2007-2009. But unless online booksellers are in on the hoax, the book is real even though its publication date is April 1.

The synopsis states that the book “brings together the key speeches made by Gordon Brown during the first two and a half years of his premiership.”

You can understand, I hope, how an someone might think it was a hoax?

When I was at university in the 70s a friend kept an LP of Andy Williams’ Greatest Hits that he would put on the turntable when he wanted the hordes of Watneys Party Seven-infused students to leave his party. Eight bars into Happy Heart and the house had cleared. One can only imagine that reading aloud from an anthology of any post-war Prime Minister’s speeches would have a similar effect on a social gathering.

If anyone was to buy this tome for a friend as, say, a birthday present, the friend would probably need to be Mrs Brown (in which case you could probably get it inscribed by the author).

The internet nominates a number of similarly boring book titles for the most yawn-inducing, including the classic When Mother Lets us Make Paper Box Furniture; The Baking Powder Controversy and the unput-downable The Value of Pi to 750,000 decimal places.

To be fair, one commentator felt moved to point out that the book about baking powder has a controversy and cannot, therefore, be entirely dull.

One blogger suggests the fifth book of The Bible, Deuteronomy is the most boring read but, if I remember correctly from being very naughty at the back of the RE class in school, there is at least one juicy chapter in there somewhere.

The publisher of Mr Brown’s book of speeches (his second volume) is quoted in The Times as saying: “We don’t expect it to challenge Harry Potter but it’s a significant contribution to the politics of our time.”

A spokesman for the Prime Minister said: “A number of people have asked him for collections of his speeches.” We can only speculate as to what that number might be.

Of the 101 uses for this book, the obvious one is to put it on the shelf with the other worthy titles you like visitors to see. These are kept at eye-level unlike the Dan Browns (top right) and the Jeffrey Archers (garage).