Trafalgar Square’s fourth plinth will welcome an artwork featuring casts of the faces of 850 trans people.

For the artwork, 850 Improntas (850 Imprints), Mexican artist Teresa Margolles will cast the faces of 850 trans people in London and beyond.

The proposed sculpture would highlight people whose “lives are often overlooked”, many of them sex workers, forming one of the world’s highest-profile public art commissions.

The casts will be arranged around the fourth plinth to create a Tzompantli, a skull rack from Mesoamerican civilisations used to display the remains of war captives or sacrifice victims.

Due to London’s weather, Margolles expects the casts to wear away and eventually disintegrate, leaving behind “a kind of anti-monument”, she told the Guardian.

The current artwork featured at Trafalgar Square’s fourth plinth is Heather Phillipson’s The End – a giant replica of whipped cream topped with a cherry, a fly and a drone – which will be on display until September 2022.

Following that will be a sculpture by Samson Kambalu, which is inspired by a 1914 photo of African independence hero and preacher John Chilembwe with English coloniser John Chorley. The sculpture will highlight Chilembwe, making him larger-than-life while Chorley remains life-size, who is wearing a hat in an act of defiance of a colonial rule that forbade Africans from wearing hats in front of white people.

Kambalu and Margolles’ artworks were chosen by the Fourth Plinth Commissioning Group after a public vote of nearly 17,500 people.

Ekow Eshun, the chair of the group, said it received more public votes than ever.