The backlash against a controversial advertising campaign for Protein World weight-loss products – which critics say promotes negative body issues – continues to grow, with a mass demonstration now planned for Hyde Park this weekend.

The advert posters, which picture a bikini-wearing model next to the slogan “Are you beach body ready?” have been branded “sexist” and “offensive”. More than 50,000 people had signed the petition at change.org by lunchtime on Tuesday calling for the posters to be removed from London Underground stations, while the Advertising Standards Authority said it had received more than 200 complaints that the advert “promotes an unhealthy body image”.

As discontent with the campaign continues to grow, activists are planning a ‘Taking back the beach’ demonstration in Speaker’s Corner this Saturday, urging people of all sizes to attend in swimwear or whatever feels comfortable.

“This was never about suggesting that people shouldn’t try to get fit if they want to,” one of the organisers wrote on the event’s Facebook page.

“If having rippling abs is your thing, more power to you. I bet you rock them. But I’m so tired of it being an expectation. The idea that your body should be covered up and hidden away if it doesn’t meet these bizarrely specific requirements…I’m over it, you guys. And judging by the response we’ve gotten on Twitter, it looks like you are too.”

Despite the opposition, Richard Staveley, head of marketing at Protein World indicated that the company was not concerned and would not be removing the adverts.

He was quoted by The Guardian as saying: “There’s more than two and a half million people who use London Underground every day and sales have considerably jumped, so regardless of that 40,000 I think I can comfortably say that we’ve had ... it’s been better for us, there’s been far more positive reaction than negative.”

UPDATE:

Transport for London (TFL) has confirmed that the adverts will be replaced from Wednesday (29 April) as they have come to the end of their three-week contract period. A spokesperson said that the campaign did not contravene TFL’s advertising standards.

Saturday's protest is still understood to be going ahead and the event's Facebook page had more than 500 confirmed attendees as of 5pm on Tuesday 28 April.

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