Rafe Heydel Mankoo of The New Culture Forum has claimed that the new sculpture is "ugly and crude" in a furious rant about British culture.
The piece, entitled "Mil Veces un Instante" (A Thousand Times in an Instant), features a towering cuboid structure made of over 300 masks depicting the faces of transgender and non-binary people.
Speaking to Emily Carver and Tom Harwood on GB News, he said: "This is ugly. It's crude, it's unimaginative, and it's so predictable in its virtue signalling.
"You can't say that beauty's in the eye of the beholder. Because the British public were polled on this when it first was unveiled.
Rafe Heydel Mankoo blasted the statue
GB News
"The images of it and only one quarter of the public had any like for it. So you have to ask given that no one wants it, why is the mayor and his ilk foisting this on us?
"It is because they're trying to create a new cultural orthodoxy for Londoners. They're trying to transform this ancient city with all of its traditions, into something new."
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Mil Veces un Instante (A Thousand Times in an Instant) by Teresa Margolles has been unveiled on the iconic fourth plinth in LondonPA"He's not just a net zero mayor. He's a years era mayor attacking all of our culture. The fourth plinth could have been used to celebrate British history.
Heydel Manko also expressed concerns about the use of public spaces, claiming: "Public spaces are for everyone to share.
"Unfortunately now if you go on the tube, you're bombarded with this messaging with anti-British poems.
"If you're on the Overground, the lines have been renamed The Public Spaces."
He added: "Britain is still overwhelmingly white British. And that shows you that the idea here is to hijack and transform this platform to promote Sadiq Khan and his divisive agenda of identity politics, virtue signalling and anti-British propaganda."
The artwork, created by Teresa Margolles, consists of a cuboid structure made up of more than 300 masks.
Each mask depicts the face of a transgender or non-binary person, with 363 individuals represented from both Mexico and the UK.
Rafe Heydel Mankoo said the London mayor is "attacking all of our culture"
GB News
The piece features personal touches, including lipstick smears and false eyelashes visible on some masks
The fourth plinth project has been a source of ongoing debate since its inception in 1999.
Some politicians have called for the space to be occupied by a statue of Queen Elizabeth II instead of rotating artworks.