One of the West End’s biggest green open spaces is to be shut for more than a year from next week as work starts on a massive overhaul.
Mayfair’s Grosvenor Square, a green oasis used by thousands of office workers, residents and visitors, will be shut for what landlords describe as “the largest private investment in public green space in the West End for a generation.”
The “radical reimagining” of central London’s second largest square - after Lincoln’s Inn Fields - follows designs from London architecture practice Tonkin Liu.
The square will close on Sunday 8th June for work to begin on Monday 9th June. The work is expected to take around 13 months to complete with a reopening in summer 2026.
The project forms part of the vision of aristocratic landowner Grosvenor - the Duke of Westminster’s family business - to “reanimate” the elite neighbourhood by drawing in more local Londoners and visitors.
There has also been concern about the lack of biodiversity in the square, which is dominated by grassy lawns and London Plane trees
It is the fourth redesign of the square in its 300-year history and is said to “pay homage to the original 1720s design”, reinstating an oval shaped lawn, framed by a new footpath and a surrounding woodland garden.
The redesigns will feature around 70,000 new plants, 44 new trees, new wetlands and c. 80,000 new bulbs, increasing planting from 140 m sq to 8,000 m sq, creating a haven for wildlife and new habitats.
The transformation is being led by horticulturalist Professor Nigel Dunnett, known for urban green projects, including the Tower of London Superbloom and the Queen Elizabeth Olympic Park. He will be working along side ecologist Gary Grant and architects BDP.
The address has long links with the USA dating back to 1785 when John Adams, the first US Ambassador lived on the Square.
This connection continued through the Second World War, where it was home to General Eisenhower’s HQ, becoming known as “Little America” due to the thousands of US military personnel working in nearby offices.
In 1960, the US opened its first purpose-built embassy building, designed by modernist architect Eero Saarinen, at the west side of the square.
With its distinctive gilded eagle on the roof, the building became a Cold War landmark, hosting generations of diplomats and playing a key role in U.S.-U.K. relations until it relocated to Nine Elms in 2018. It was the scene of clashes between anti-Vietnam demonstrators and the police in 1968.
The former embassy building is reopening as the Chancery Rosewood hotel in September.
The Square features memorials to Franklin D Roosevelt, the Eagle Squadrons and a garden of remembrance commemorating the 67 British victims of the September 11 attacks in 2001.
Over 7,000 people fed into the designs, which included a public vote to select flowers for the garden.
Responding to this, primroses, bluebells and honeysuckle will feature prominently as part of the 80,000 new bulbs set for the square, creating a “carpet of colour” for months throughout the year.
The redevelopment includes a new education building, where programmes funded by The Westminster Foundation will offer opportunities for children and adults to learn about biodiversity, the environment, climate change and the square’s history. Providing further community benefits, a new kiosk serving refreshments, public toilets and 300 additional places to sit will be provided.
There will also be additional CCTV and new lighting installed that will enable the square to provide a safe environment and the square to stay open later into the evening.
The Duke of Westminster said: “Our ambition is for Grosvenor Square to once again become a treasured green space for everyone to enjoy and where people of all ages can reconnect with nature in the heart of the city.
Building on its long history, this revitalisation will breathe new life into the square for current and future generations. From increasing biodiversity to creating new opportunities for learning and education, the transformation has been shaped by the thousands who shared their ideas and voted on the design. We’re deeply grateful for the community’s support.”
James Raynor, CEO, Grosvenor Property UK said: “Grosvenor Square will be one of the world’s most outstanding and innovative urban green spaces, responding to the climate emergency whilst inspiring joy, delight and wonder.”
“This voluntary investment for the benefit of the public epitomises our unique role as custodians and long-term stewards of Mayfair. It is testament to our commitment to placemaking, environmental leadership and community engagement, and will ensure Mayfair remains a pre-eminent place to visit, live and work.”
Mayor of London, Sadiq Khan, said:“As the world’s first National Park City, it’s great that a new green haven is being created in Grosvenor Square in the centre of London where wildlife will be able to thrive.
“This private investment is fully aligned with our ambitious London Growth Plan and will lead to a transformation that will blend beauty and biodiversity to create a place for visitors and residents to reconnect with nature.
“I look forward to seeing the transformation of Grosvenor Square into another of London’s world-leading urban green spaces as we continue building a greener, more prosperous London for all.”
Nigel Dunnett, Professor of Planting Design and Urban Horticulture, University of Sheffield said:
“We are looking to set a new standard for biodiverse public spaces in the capital, bringing the exuberance of a rich natural environment into a London square in a way that hasn't been done before.”
“Through an innovative and ambitious approach to planting, we are championing sustainability and climate-adaptation, swapping low diversity amenity grassland for sparkling flowering lawns, and creating extensive areas of new woodland plantings beneath the existing London Plane trees, to create new wildlife havens and gardens that will look fantastic year-round.”
Alex Clarke September 11 family member said: “For many years, the Memorial Garden in Grosvenor Square has been a highly valued place of peace and remembrance for the families of the 67 British victims of the September 11 attacks.”
“As a family member, a passionate amateur gardener and former Grosvenor Square volunteer, I’m thrilled that the square is set to become a place of natural tranquillity. Its rich landscape and birdsong will enhance the memorial’s setting and offer a calming retreat from the hubbub of daily life.”
