A Twitter campaign has backfired on Waitrose, Britain's most upmarket supermarket, after the brand -- part of the John Lewis Partnership -- asked its followers to finish the sentence: "I shop at Waitrose because..."

Waitrose created the hashtag #waitrosereasons and sat back, expecting to soak up the praise.

The hashtag did indeed go viral -- but surely not in the way that Waitrose had intended. It bypassed the supermarket's fans and found its way into the tweets of those who wanted to bring the posh people's supermarket down to size, with some traditionally class-based British humor.

The reasons tweeted for shopping at Waitrose included, "Because I was once in the Holloway Rd branch and heard a dad say, 'Put the papaya down, Orlando!'" Others included, "I shop at Waitrose because darling, Harrods is just too much of a trek mid-week" and "Because my butler is having a week off."

Others took more of a class-war stance, such as, "So people know I'm filthy rich and therefore automatically better than they are," while others went for more lavatorial humor, with suggestions including, "Because I like putting my willy in their hummous," and "Because I got a lifetime ban from M&S after doing something obscene to a Percy Pig."

Jim Coleman, managing partner of We Are Social in London, said, "I think they genuinely wanted some insight from their customers, and opportunistic punters took the opportunity to play on the middle-class stereotype that Waitrose has. They didn't react quick enough or with a clear plan. It shows why being prepared with a crisis plan is key to your social comms, whatever brand you are."

There were a smattering of tweets from the target market, however, with appreciations such as "Because I like the way they treat their staff, suppliers and customers" and "Because you can rely on it stocking all the items you will need for your recipe."

A Waitrose spokesperson said, "It certainly provoked a reaction but we like to hear what people think. We've thanked everyone for the genuine and funny tweets." Waitrose itself bravely tweeted, "Thanks for the genuine and funny #waitrosereasons tweets. We always like to hear what you think and enjoyed reading most of them."

Opinion on Twitter was split over whether or not the #waitrosereasons campaign backfired. Maxim PR tweeted, "Whoever runs the @waitrose account seems to have handled #waitrosereasons pretty well. We're talking about the brand so it that a success?"