Grosvenor Square revamp: London's most dramatic water feature proposed for Mayfair garden square

A cavernous subterranean water garden up to 50 metres across is at the heart of a proposed makeover of one of London’s biggest squares.

The capital’s most dramatic “water feature” will be under Grosvenor Square in Mayfair, the second largest in the capital after Lincoln’s Inn Fields.

A public exhibition of the proposed changes describe how it would be sited under a “gently rising mound of grasses and plants.”

The garden, part of plans drawn up by the Duke of Westminster’s family property company Grosvenor Britain & Ireland, would be a “celebration of rain” where “water will be absorbed into a sponge like roof, filtered and then transported around the square for use in watering and storage.”

The overhaul would see the six-acre space transformed to increase biodiversity and double the number of trees. Currently it is dominated by just three species — grass, London planes and a holly hedge.

The proposed new design would create four interlocking gardens around a central oval space inspired by the original 1720 layout.

Ed Green, senior development manager at Grosvenor Britain & Ireland said: “The proposals deliver what people have told us they want through the engagement process. They offer a balance of different areas for nature and people without over-crowding the space.

“They show how garden squares can play their part in tackling the climate emergency, by bringing as much nature and biodiversity to the site as physically possible while addressing the issues that are important for multiple generations of visitors.”

Anna Liu, director, at Farringdon based architects Tonkin Liu, which drew up the plans, said: “Many of those we have spoken to wanted us to create an active living landscape for London. Our designs build on a growing desire to enjoy and explore local green space across the year.

“By proposing four different gardens in the square we have been able to extend the open space that is currently valued but also create new areas where people and nature can thrive together. This is about an active living landscape for London.”