This is where Astra's lack of experience in vaccines really tripped it up - managing expectations through simple and effective communication.
From the start, its efficacy numbers were hard to grasp, with separate numbers for different age groups.
Questions were asked over sample sizes in over 65s and efficacy numbers submitted to US regulators had to be revised down when more up-to-date results were included.
None of these made much of a difference to the overall picture - one of a safe and effective vaccine - but it fostered an impression the company was not being entirely competent, or entirely honest.
One source told the BBC that "if you looked on an organisational chart of AstraZeneca, the box labelled vaccine management wouldn't have much in it".
The company has already said it will review the status of its "not-for-profit" stance on its vaccine work when current contracts have been fulfilled.
But Sir John says he can't blame the firm, "given the way they have been treated".
A major investor suggested that when the contracts are fulfilled, this could be a moment the management review whether they want to be in the business at all. pgslot