When we last met, David Craig said he wouldn’t be writing another book because ‘not enough’ people were buying the ones he had already written.

The Great European Rip-Off, Rip-Off Squandered, Pillaged and Fleeced, not to mention Greed Unlimited; all having a multi-pop at bankers, insurers, dodgy financiers, waste, politicians, Europe...

But I’m not surprised to find myself back in his immaculate penthouse flat, seagulls swooping over the terrace, as he outlines, in his gentle Scottish accent, just what he wants to draw our attention to in his wittily-named tome Don’t Buy It.

Chicken questions and nodding donkeys; decoy questions and khazi closes. Not to mention the perennial ‘back-ending’. In a word, the tricks used by: “Salespeople.”

Not all sales people, you understand – he was one himself – just those who are either casually or determinedly ripping us off.

Three things triggered the book, he says. “When I came back to Britain from abroad I felt I had been completely fleeced when I bought my car and a house.”

This he could live with – nothing illegal occurred – but one day: “I was in a bank sitting outside the offices of the manager.

“I heard two young guys laughing and joking, so I listened in.”

He learned they were financial advisers working for the bank and had advised a pensioner to put ‘virtually all his life savings’ into one fund.

“That fund had lost about half its value in two or three years and the pensioner had rung up,” he says.

“They were laughing about what a sucker he was to put money in there but were also afraid he was going to complain so they were trying to cobble together some excuse to fob him off. This really got me thinking.”

When David thinks, David does, so he started attending lots of ‘seminars and financial services stuff’ and reading about exactly what can happen when salesmen go bad.

Although he knew some of the tricks and tips associated with selling, such as the advice to ABC – Always Be Closing (your sale) – he was amused and alarmed to learn of the rest.

“What I’m trying to do is by showing the names of these tricks and explaining how they work how readers can look out for them,” he explains.

One of the most popular is, he says, the Valley of Death, which is a ‘key fear-selling technique.’ “The fact is that most people and most organisations will not give you large amounts of their money if they are reasonably satisfied with the way things are,” he says.

“So you have to shock and frighten them and give them a near-death experience.”

These could be as simple as telling a married couple about another couple who were left destitute because they didn’t save enough for their retirement. For businesses it could be ‘gruesome descriptions’ of other companies who plunged from profit to loss because they were “Too short-sighted or niggardly to use a seller’s services.”

Then there’s the ‘chicken question’, apparently beloved by sales staff because it shows “We are just about to buy from them and only need a few concerns overcome before handing over our cash or plastic.”

‘What if I take it home and it doesn’t fit properly’ is a standard chicken question.

‘Nodding donkeys’ are a series of questions to which the buyer will answer yes, leading to the actual sale: “You are more likely to agree if you’ve been agreeing all along.”

And the delightfully-named Khazi Close, according to David, is when sellers in your home would ask to use the loo, then, as they leave, switch on a microphone in their briefcase and listen to what you’re saying when they think you can’t hear.

And Backending? This, according to David, is the kind of stuff that anyone trying to flog us a pricey piece of equipment endeavours to get us to buy, to beef up their profit margin; all the warranties, service agreements and sound-system upgrades.

David fell for something called ‘Gap insurance’ where he paid £400 so that the gap between his existing insurance and the price of his car if written off would be covered.

“I wrote to them afterwards and said I don’t think this was sold properly and they sent me a cheque for £400,” he says.

But he’s happy to confess it was a while before he worked out that an extended warranty of three years is actually only two; when you add in the free year that everyone gets on these things.

But he doesn’t have a down on salespeople; they have a living to make and we have to buy stuff.

“It’s not wrong to sell things,” he declares. “There’s nothing wrong with selling things which will benefit people. What’s wrong is spotting people’s character weaknesses and selling to those.”

Don’t Buy It by David Craig is available from snouts-in-the-trough.com