The concept creates a memorial walk formed of dozens of lily pad ‘stepping stones’, with a centrepiece statue of the Queen shaded by eight sculptural lilies.

We have provided structural engineering input on the exciting proposal, including stone expertise, collaborating with sculptor Halima Cassell, landscape designer MRG Studio, material specialist The Stonemasonry Company, and engineering practice Arup. The structure is conceived with sustainability and durability at the forefront, using naturally durable and beautiful load-bearing and post-tensioned stone as the primary structural material.

The fluted form of the lily pads gives opportunity to create a structurally efficient compression only shell structure with a mathematically derived form-found geometry. Mimicking gothic groin vaults curved stone pieces will form a loadbearing shell between post-tensioned stone ribs erected off central solid post-tensioned stone columns to minimise temporary works and give stiffness along support lines for the deck.

Radial tension cables within the shell edge create a perimeter tension ring to resolve thrust forces. Discrete columns springing off the ribs in turn support a loadbearing stone deck which uses arching to efficiently span whilst minimising material and weight.

Each lily pad is stable in its own right with the sequence of interconnected lily pads resolving out of balance forces and creating a continuous structural form, symbolising the spirit of togetherness.

A panel of committee members will select the winning concept and work with the team on the final design, which is expected to be unveiled in 2026. The final design will then be submitted to King Charles and the prime minister for approval.

The five shortlisted designs can be viewed in the Finalists’ Gallery, open to public feedback until 19 May.