Theresa May blank eyes. Matt Brown / Flickr. Some rights reserved.

There is an old commercial maxim, which states you don’t close a sale, you just open a relationship. And if it stands a chance of surviving, there has to be a degree of honesty: as the saying goes, you can’t sell a doughnut if you don’t acknowledge the hole.

No one holding responsibility inside the Conservative campaign team seems to have understood this, or any other basic principle of selling. The result has been a badly-packaged election pitch which has tried to offload Theresa May as a strong and stable leader, when those with experience of her, especially at cabinet level, knew this was always going to be a suspect product unlikely to pass any stringent consumer test.

May as a charismatic politician, capable of using her personality to shoulder a cultish, crowd-pleasing campaign where leadership sidelined everything else, now seems like a fantasy dreamt up by bargain-basement advertising agency.

Yet that is what the British electorate have been being asked to buy. And over the course of the election, if polls are correct, they have seriously hesitated.

As the election campaign closes, there is a degree of group despair among some of the more corporately savvy Tory figures, which suggests that even if May wins, regardless of the scale of the victory, she will never again be asked to front an election campaign.

One senior insider told openDemocracy: “The last six weeks have been a hard lesson. People may still buy her. But will we risk betting the entire family silver on her again? No. That will not happen. The hunt for a new leader is, sadly, already under way.”

Six weeks ago a carefully evaluated sales strategy was seen as unnecessary, an indulgence even. The Prime Minister enjoyed a 20-point lead over Jeremy Corbyn, an opponent so ill-equipped for office that the vast majority of his own parliamentary party prayed for a humiliating defeat, or one just damaging enough to force a return to the back-benches from whence he came.

In the world of sales, this is dangerous territory to be in. Whenever a business decides that success has been achieved, progress usually stops. Politics is no different.

Having dismissed the need for an election on multiple occasions, May based her U-turn on the assumption of guaranteed slaughter. The excuse of improving her weaponry for the imminent fight against Brussels sounded only faintly plausible.

In sales who controls what someone buys is an important concept. And it’s customers decide. If they believe you have already made the decision for them, that you are trying hard to control the process, they don’t like it and begin to look around for alternatives.

If they believe you have already made the decision for them, that you are trying hard to control the process, they don’t like it and begin to look around for alternatives.

May looked awkward, joyless and robotic as she delivered the campaign messages designed by Sir Lynton Crosby. Her decision to refuse any confrontational TV debates, suggested she believed she was above popular accountability. The electorate had a right to vote, but why they should vote for her was none of their business.

Delivered by an empathetic, highly loved authoritarian politician, such a strategy might be understood. But Theresa May has never fronted a major campaign nor played a leading role in a critical election.

It’s dangerous in sales to approach a deal with the preconception that the customer wants what you are selling. It’s equally unwise to assume what the customer is thinking. Yet that is exactly how the Tory campaign was geared.

The presidential pitch May repeated, again and again and again, was that only she was capable of turning the office of prime minister into a general-in-chief. Forget the Conservative Party; this was her election, her campaign. She was the only choice.

Did she deserve this approval? On what information would consumers buy her? They say in sales that the most effective technique comes from listening to, rather than talking at, people. But in tense, jittery, wooden, often flat performances, it became clear that explanation formed no part of the Tory bargain being offered.

If the Brexit negotiations needed an improved mandate, what would May do with her increased authority? How would this deliver a better Brexit, a better deal?

Consumers buy products they believe will improve their lives. The higher the benefit, the higher the price. Someone’s vote is a major decision, similar to a major purchase, something that happens only every few years. People can change cars more often than they vote. They shop around, acquire detail, ask about value.

So what was May going to do with all this approval if she won? Beyond “strong and stable leadership” the electorate are still in the dark. Brexit remains a black box of hidden consequences. Where information was needed, there was none. She was instead merely saying: ‘Vote for me. I deserve your vote because I’ve told you I’m strong and stable. ‘

One adman, who worked on Labour’s “Shadows” campaign in 1987, said “Selling Theresa May as they’ve tried to do, is one of the most insulting campaigns I’ve come across in the last 20 years. When an ad agency takes the piss, and assumes consumers won’t notice, it usually spells disaster – and a lost account.”

In sales, before a product can be successfully marketed, a number of key questions must be answered. Does the product break through above other noise? Will people want to know more? Will it give them something they don’t have? Will it capture their hearts or minds? Will it engender belief or trust? People buy what they like, so what will convert them?

In the post-referendum internal warfare that followed the resignation of David Cameron last year, and after the fratricide that took out Boris Johnson and Michael Gove, Theresa May and Andrea Leadsom emerged as the two left standing. Leadsom was seen as a potential disaster-in-waiting and was persuaded to exit gracefully, leaving May the keys to Number 10 without facing any challenge.

The campaign designed for her seems to have forgotten this. She has never been a noisy, profile politician. There is nothing standout about her. Likeability has never been discussed. She openly says, “I am not showy.”

What is equally obvious is that she is not a conviction politician either. Though a remainer, a week after the referendum she offered “Brexit means Brexit”, ditching her previous position. There have been other U-turns on a UK bill of rights, on nuclear energy, national insurance, energy policy, and during the campaign on social care. Yet the election sales campaign projected her as a new Thatcher, a needed Churchill, the Wellington required for an imminent Waterloo. “Strong and stable” was offered without explanation.

Why Corbyn broke through, why he gained credibility against all expectations, and how a badly misjudged Tory manifesto resurrected Labour’s hopes, will all be dissected in detail.

But it is the misjudged selling of Theresa May that may yet be the signature failure of the 2017 general election. The Tory campaign scared off potential customers. How much that let in competitors we will soon know.