Local Authority: City of London

Client: Reignwood

Architect: Auckett Swanke

Contract Value: £175m

Ten Trinity Square

The redevelopment of Ten Trinity Square is one of the London’s most iconic recent projects. Having opened its doors to a global fanfare as one of the World’s best new hotels, we have transformed the former headquarters of the Port of London Authority into a stunning Four Seasons hotel and residences.

Situated in the heart of The City of London, the building at Ten Trinity Square is one of London’s most treasured buildings, having once been the seat of power for both the Port of London Authority and the United Nations.

The Sir Edwin Cooper designed building was originally built in 1922 and occupied by the Port of London Authority until 1970. In 1946, the building hosted the inaugural assembly of the United Nations in 1946 and was later used for the famous signing of the first UN Charter in 1948, hosted by Winston Churchill.

In the latest chapter in its extraordinary life, the Grade II* listed building has undergone a meticulous conversion, with Ardmore overseeing the sensitive refurbishment and transformation into a spectacular Four Seasons Hotel and apartments.

The Four Seasons at Ten Trinity Square

Completed in early 2018, the hotel provides 100 guest rooms and 41 serviced apartment, two restaurants – La Dame de Pic London and Mei Ume – and the Rotunda Bar; the historic UN Ballroom, a second function room called Merchants’ Hall, a suite of club and meeting rooms on the second floor and a luxurious spa and fitness centre.

The 41 luxurious apartments have been constructed around a new elegant glazed rotunda in the courtyard, which references the original rotunda damaged during the Second World War

Ardmore was the main contractor for the majority of the project, from excavating a new basement under the existing building to the luxurious fit-out of front of house areas, guest rooms and apartments.

Heritage Restoration

We also carried out the sensitive restoration of the building’s listed meeting rooms. Now providing meeting rooms and facilities for the private members’ club, these areas retain the sumptuous boardrooms and executive offices of the original building through a careful restoration of all the finest features of the carved walnut panelling and high ceilings.

Our own team of specialist craftsmen and artisans worked closely with architect Aukett Swanke to carefully repurpose the existing spaces in the building, inserting new elements, textures and materials to create a thoroughly contemporary blend of history and hospitality.

Extensive Structural Interventions

A new basement, excavated under the existing building, posed additional structural and archaeological challenges while the coordination of services through the new elements and existing historic fabric was essential to the success of the scheme.

The complex routing and access requirements of the building’s heating, ventilating and air conditioning systems, which include a combined heat and power unit, has required the building services team to pay special consideration to prevent damage to any of the heritage areas and particularly ceilings. Extensive coordination has been required for all the basement areas and risers to help determine the optimum fresh air inlet paths for ventilation, due to the building’s previous reliance on natural ventilation.

The complex builders work posed a number of structural and archaeological challenges. Our in-house capability for designing and undertaking the works whilst co-ordinating services through the new elements and existing historic fabric was essential to the success of the scheme.

We installed a low water use mist system rather than a traditional sprinkler system to reduce the required water storage requirement for the building.

The building has a number of mixed-uses, each requiring specialist control systems. These systems enable the building operator to manage the building effectively under various scenarios and conditions.

Award Winning Performance

Ten Trinity Square was named AA Hotel of the Year London 2018-19 at the annual AA Hospitality Awards, as well being awarded 5 AA Red Stars and Conde Nast’s ‘Best New Hotel Opening in the World’ 2018.

The Mei Ume Restaurant in the hotel was named Best Overall UK Restaurant at the 2018 Restaurant and Bar Design Awards, and also winner in the Luxury Restaurant category.

The hotel was Runner Up in the 2017 City of London Building of the Year Awards and shortlisted in the ‘Listed Buildings over £5m’ category in the 2017 Architects’ Journal Retrofit Awards.

Company Profile


The Ardmore Group is one of the largest wholly family owned and run construction companies in the UK. Founded by brothers Patrick and Cormac Byrne in 1974, the group remains a family-owned and family-run business to this day.

We’re well known for our extensive in-house capability and pro-active approach to delivery, which gives us the confidence to provide a cost certainty and a fixed price approach on major projects. By retaining direct control over critical work packages, we build resilience into our supply chain and take total ownership over delivery, cost and quality.

We have been at the forefront of London residential and luxury hotel sector for over a decade. In that time we’ve not only delivered some of the capital’s highest profile residential schemes like Chelsea Waterfront, Chapter House and Canaletto, but we have also delivered two of the World’s best new hotels: The Four Seasons at Ten Trinity Square and the Ned.

Our portfolio of London’s best prime and super-prime residential projects speaks for itself. Put simply,  high build quality is embedded in everything we do.

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