Media playback is unsupported on your device Media caption Walkers asked people to send in selfies, but some took advantage

You might have thought that big brands would have learned their lesson by now - even the best ideas can get away from you when social media users get their hands on them.

And Walkers Crisps' marketing managers have found that out the hard way.

Within hours of the launch of a Champions League final campaign, which included the chance to win tickets for next weekend's Cardiff showpiece, their crisp-eater-in-chief Gary Lineker has been pictured clutching photos of Fred West and Harold Shipman in online videos on Twitter.

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The "Walkers Wave" campaign asked social media users to respond to a tweet from the official Walkers Crisps Twitter account with a selfie, using the hashtag #WalkersWave, as part of the chance to win the tickets.

The user's picture would then be incorporated into a personalised video, featuring Gary Lineker, automatically tweeted and captioned by Walkers.

Image copyright @Walkers_Crisps

But, almost inevitably, pranksters online saw the potential.

Sensing a flaw in Walkers' marketing plan, people on Twitter started to respond with pictures of serial killers and disgraced celebrities.

Image copyright @Walkers_Crisps Image caption One social media user tweeted an image of Harold Shipman, one of Britain's most prolific serial killers.

Image copyright @Walkers_Crisps Image caption Continuing the serial killer theme, another user tweeted an image of Fred West.

In response, Gary Lineker tweeted: "Had an unusual day in some very strange company. I'm sure we'll wave goodbye to them all by tomorrow."

Image copyright Twitter

Launching the campaign earlier this week, Adam Warner, head of UEFA Champions League sponsorship at PepsiCo, said:

"At Walkers, we celebrate the fans who love the social occasion around UEFA Champions League match nights as much as the games themselves.

"Moments that bring fans together like a fan wave are an important part of a football game."

Walkers have started to remove the automated tweets and a company spokeswoman told the BBC: "We recognise people were offended by irresponsible and offensive posts by individuals, and we apologise. We are equally upset and have shut down all activity."

By Chris Bell, UGC and Social News team