One Portsoken Street, London, Transformed Into Grade A Office Space with Sustainable Lighting Solutions

March 29, 2023
DALI-enabled LED emergency luminaires aid efficiency, while ensuring compliance with legislation and helping One Portsoken Street's total building retrofit to achieve high-level building certifications from BREEAM and WiredScore.

One Portsoken Street, London

Located on the outskirts of the City of London, One Portsoken Street is an office block originally built in the 1980s. Having fallen into disrepair, the building needed to be completely overhauled to provide modern office space in an enviable location.

Alfred Equities led the regeneration of One Portsoken Street. Known as a forward-thinking developer, the firm recognised the huge potential of the space. To deliver the refurbishment of the site, which at 230,000 sq ft of space was the largest design and build project in the UK, Alfred Equities appointed leading office design company Oktra. 

The transformation of the site by Oktra would offer Grade A office space, maximising the interior to add 20% more lettable space without having to build any additional floors. Given the building’s heritage, it was also important to restore the original architecture, but still give One Portsoken Street a new identity that would attract tenants and become a desirable location.

The upgrade fulfilled both BREEAM and BCO design standards. Oktra specified solutions from Mackwell to ensure the emergency lighting technology met these important sustainability standards. 

Quartz Project Services were also heavily involved in the regeneration of One Portsoken Street, acting as project manager.

Intelligent Emergency Lighting Systems  

Mackwell, a global manufacturer of emergency lighting technology and system, provides clients with a full emergency lighting solution from system specification to commissioning.

In One Portsoken Street, Mackwell’s XYLUX LD5 DALI has been installed. This high-performance, self-contained LED emergency luminaire is supplied with two snap-in optics for Open-Area and Escape Route distribution. The XYLUX LD5 LED luminaire incorporates a LED module, a 3.6V 1.7Ah NiMH battery pack and a deep discharge protection circuit.

The addition of DALI offers the benefit of enabling testing and monitoring of an emergency lighting system, either on-site or through an internet connection. DALI AutoTest® is ideal for monitoring larger buildings, which is ideal for the huge footprint covered by One Portsoken Street.


The building was completely gutted and what was one the largest atrium in Europe has now been filled through the installation of 27 piles at a depth of 20m. This has delivered a 20% increase in lettable space, which met the original brief. 

Options for floorspace vary from 10,000 to 30,000 sq ft, and are designed to accommodate three separate tenants. New features include high exposed ceilings, excellent natural light filtering throughout the building, and an impressive lobby space with a two-and-a-half-storey atrium. Nine new lifts have also been installed to offer better access around the offices, which is particularly important given its large footprint. 

As a result of the upgrade to the building’s infrastructure, One Portsoken Street has achieved a ‘Very Good’ rating from BREEAM. The office block also has a WiredScore Platinum certification, the highest-awarded WiredScore mark proving that the building meets exceptional standards for the quality of its wired infrastructure, resilience, and wireless network.

DALI enabled LED emergency luminaires, such as Mackwell’s XYLUX LD5 DALI aids efficiency, while ensuring compliance with legislation. 


Mackwell is one of the leading providers of technology solutions for the global lighting industry, with ties to many major international companies in over 40 markets and export business.

With a background firmly grounded in electronics, Mackwell has developed a wealth of experience in lighting throughout the World and an enviable reputation for the design and manufacture of reliable, innovative electronic components. This enables the company to provide customers with innovative solutions that give them a competitive edge in their target markets.Mackwell embraced LED technology and DALI early in their inception which has allowed the company to continually evolve with the latest developments and bring state-of-the-art solutions to market. Mackwell has also kept abreast of the reduction in size of luminaires as LED’s become more popular, supplying products to meet the need for fitting into more compact proportions. Operating from our purpose designed R&D and manufacturing facility in the heart of England, Mackwell's philosophy of never leaving safety to chance has led to the design of a portfolio of high quality, durable emergency products for a wide range of applications.