Cadbury’s “racist” advert which offended supermodel Naomi Campbell should never have been allowed to see the light of day, according to a brand reputation expert.

The supermodel accused the company of racism after an advert appeared to liken her to a chocolate bar with the slogan “move over Naomi, there’s a new diva in town” – although Cadbury insisted it was “a light-hearted take” on the social pretensions of Cadbury Dairy Milk Bliss.

The PR blunder for Cadbury comes as the refusal of Kraft boss Irene Rosenfeld to answer questions from MPs continues to cast a shadow over Kraft’s corporate reputation in the UK.

Earlier this week she claimed attendance at hearings of the Business, Innovations and Skills Committee was “not the best use of my personal time”.

Jonathan Hemus, who has worked on brand issues with companies such as Disney and Proctor & Gamble, said he was surprised the Dairy Milk Bliss campaign ever got beyond the drawing board.

“They should have done a proper reputational risk assessment on the campaign, and if they had done that then I can’t believe they would have gone ahead with the advertising campaign.

“Sometimes in a quest to be memorable it is possible to allow the advertising to go way beyond what is in keeping with the brand and what is in keeping with taste and decency.

“They may have come up with an advert which is memorable, but not one which is helpful How that was allowed to happen – my guess is as good as yours – it does not seem to be very well-judged.”

Since before the take-over of Cadbury, Kraft has been warned of the importance of preserving the value of the Cadbury brand, built up over more than a century to one of the best-loved corporate names in the country.

In January last year Sir Adrian Cadbury and Sir Dominic Cadbury penned a newspaper article in which they described the company’s reputation as “an asset of incomparable value”.

But since Kraft took over several high-profile members staff have left, including many in the advertising and creative team, raising fears the Cadbury brand could suffer under Kraft stewardship.

Mr Hemus said: “It could be that the corporate memory and corporate understanding of what the Cadbury brand is all about is leaving with the people that are leaving as a result of the Kraft takeover.”

Ms Rosenfeld’s reluctance to publicly answer questions about the takeover of Cadbury was more of a Kraft reputational issue than a specifically Cadbury one, Mr Hemus said.

“Her unwillingness to engage is very damaging to Kraft’s reputation and is not a well-conceived corporate reputation management strategy, but it is unlikely to do damage to the Cadbury brand itself,” he said.

“People love Cadbury products and the reality is it will take an awful lot to get people to boycott Cadbury and stop eating their products.

“But it is damaging to Kraft’s corporate reputation and may well do damage internally in terms of staff morale, further damage in terms of community relations in the Midlands and it will sour relations with MPs.”

Meanwhile the unions are not happy with Kraft’s style of communication either – they are still looking for information on Kraft’s plans for the Cadbury workforce in the city and are calling for guarantees on jobs and investment.

Jennie Formby, Unite’s national officer for the food and drink sector, said: “In fact we now have less information about the company’s current state and future intentions than before the takeover.”