Reform UK spokesperson Zia Yusuf has demanded that Green Party leader Zack Polanski be arrested following a controversial social media post. Police are “conducting inquiries” into an image shared on social media, after Reform UK reported Mr Polanski over a picture on his Instagram.

The image, which was subsequently unshared from Mr Polanski’s account, featured a man wearing a black T-shirt with the message “We’re only making plans for Nigel” and an image of a guillotine. Reform UK’s spokesperson for home affairs Zia Yusuf said Mr Polanski was “inciting murder”, adding that sharing the image weeks after the death of Ann Widdecombe was “staggering”.

He wrote on X: “If Zack Polanski is not in police custody by this time tomorrow, the Police will have declared open season on Members of Parliament.”

Making Plans For Nigel is a song by English rock band XTC, released as the lead single from their 1979 album Drums And Wires.

A post on a website appearing to sell the T-shirt for £20 stated: “Who could Nigel be? And why the guillotine?

“Whether it’s a nod to old punk music or a sharper bit of political satire, this design is for those who prefer their statements with a side of mystery.”

Sharing a screenshot of the image, Reform UK leader Nigel Farage wrote on social media: “This is what Zack Polanski has just posted on his instagram.

“If I was to post anything as inciteful then I would expect to be arrested, and so should Polanski.”

The Green Party said Mr Polanski “condemns the image on the T-shirt” and clicked accept to be tagged in a post with 20 images “without realising there was more to it than he had seen”.

The image comes just weeks after the murder of Reform UK spokeswoman Ann Widdecombe.

Prosecutors told a court last week that a man allegedly hit the former Tory minister 21 times over the head with a hammer in a “planned and targeted” attack.

A Green Party spokesperson said: “Zack condemns the image on the T-shirt. He was tagged in a post with 20 images and clicked accept without realising there was more to it than he had seen.

“The T-shirt is clearly in poor taste, especially at a time of heightened fears for the security of public figures having experienced multiple threats himself.

“He and the Green Party call on everyone involved in public discourse to show kindness and not encourage more division.”

A spokesperson for the Metropolitan Police said: “Earlier today – Monday, 27 July – we received a third-party report relating to an image shared on social media.

“We take reports of this nature extremely seriously, and officers are conducting inquiries into the matter.”