A blimp of Sadiq Khan wearing a yellow bikini is to fly over Westminster on Saturday morning in response to the Donald Trump baby balloon that the London mayor permitted in July.

A crowdfunding campaign has raised more than £58,000 for the blimp, which references the bikini-clad “body-shaming” adverts Khan has vowed to ban on the tube. Organisers says they want to highlight the rise in violent crime in London this year.

Yanny Bruere, a self-described free speech advocate, is behind the Make London Safe Again campaign. “Under Sadiq Khan, we have seen crime skyrocket to unprecedented levels. People in London don’t feel safe and they aren’t safe, [there have been] 81 murders this year alone,” he wrote on the blimp’s Crowdfunder page.

The blimp gives Khan him a somewhat stern expression. Photograph: @YannyBruere/Twitter

“In light of the ‘Baby Trump’ balloon being allowed to fly over London during his visit to the UK, let’s get a ‘Baby Khan’ one and see if free speech applies to all and whether or not Mr Khan and the London assembly will also approve this.”

Khan said: “If people want to spend their Saturday looking at me in a yellow bikini they’re welcome to do so. I don’t really think yellow’s my colour though.”

By Thursday afternoon, more than 700 people had signed up to a Facebook event page calling for people to gather in Parliament Square to watch it, while about 4,800 indicated that they were “interested”.

A city hall spokeswoman said the organisers of the blimp’s flight had been given permission to use Parliament Square Garden. “As always, city hall has been working in very close co-ordination with the Metropolitan police and other key agencies to ensure this protest is able to be carried out in a safe and secure way.”

Trump supporters were infuriated when Khan allowed protesters to fly a blimp depicting the president as an orange-skinned baby clutching a mobile phone, in a nod to his outbursts on Twitter.

Bruere’s blimp highlights Khan’s nose, and dresses him in a yellow bikini – a reference his 2016 call to ban “body-shaming” advertising on London’s transport network. Khan’s intervention, one of his first acts as mayor, followed an outcry over a protein shake poster featuring a model posing in a yellow bikini with the text: “Are you beach body ready?”