Every Edinburgh Fringe needs a controversy and this year, perhaps unsurprisingly, the big controversy is the comedy show being performed by Amanda Knox, the American who was convicted and later acquitted over the murder of British student Meredith Kercher in Italy back in 2007.

A petition calling for the show to be cancelled – set up by Sally Alington, a friend of the Kercher family – has now passed 40,000 signatures. But Fringe bosses and the Gilded Balloon, where Knox is performing, as well as Knox herself, have all defended the show.

The official blurb for ‘Amanda Knox: Cartwheel’ says that “Amanda Knox is approaching 40, juggling motherhood and finally getting around to being furious about the whole wrongful-imprisonment thing. Especially when half the world is telling her to get over it, while the other half still thinks she’s guilty”.

In an introduction to her petition, Alington says that Knox’s show “mocks the horrific events surrounding Meredith’s murder and aims to somehow turn this tragedy into entertainment”.

Meredith’s siblings, she then explains, “have bravely spoken out against this production, labelling it as absurd and a gross trivialisation of their sister’s death”.

“This show not only disrespects Meredith’s memory”, Alington adds, but “also risks normalising violence against women by making light of such a harrowing event”.

Speaking to the BBC, Kercher’s sister Stephanie said that Knox is “naturally free to continue with her life as she wishes, but I think the problem with this particular project is that it is comedy”.

“And whilst I appreciate comedy is there to push the boundaries”, she added, “it very much normalises and trivialises violence against women and Meredith in particular”.

Knox herself has responded to the petition on Instagram, insisting that her show “honours Meredith Kercher’s memory and calls out the violence that was done to her and to me”.

‘Cartwheel’, she insists, is “a show about motherhood, raising a daughter in a world that is unfair and dangerous for women, and what it costs to be the kind of mother who tells her the truth about that”.

She then adds, “a petition to cancel a show no one has seen, on the grounds of false accusations intended to shame and vilify a wronged woman into silence, is not an argument against ‘Cartwheel’. It’s a fairly precise description of what ‘Cartwheel’ is about and why it deserves to exist”.

In a statement responding to all the controversy, Gilded Balloon stresses that the Edinburgh Fringe “is an open-access festival”, and that “artists and companies choose to participate at our venue and take on the financial and creative responsibility for their work”, and that Amanda’s show “is a one-woman piece exploring themes of motherhood, presented independently by her.”

However, it adds, “As a Fringe venue, we provide a platform for a wide range of voices, in line with the Fringe’s longstanding commitment to freedom of expression – within the confines of the law – and ensure our audiences can make informed choices”.

Asked about the show by BBC Radio Scotland, Fringe Society boss Tony Lankester said that, “when you open up your stages and invite people in to tell their stories without censorship, any curation and without trying to control the content ahead of time, you’re inevitably going to end up staging things that cause discomfort and push the boundaries”.

“If anyone wants to use the Fringe to break the law, to incite violence or to embark on hate speech, that is our red line and we would intervene”, he then explained. But “for us, the baseline principle is the Fringe is a platform for free speech and some people may not regard it as being in good taste but we cannot apply that criteria because who decides that?”