International arbitration law firm Three Crowns has signed for 15,484 sq ft at Helical and Ashby Capital’s The JJ Mack Building in London.
The firm has signed a 15-year lease on the space at 33 Charterhouse Street, EC1, and intends to relocate from its existing offices at New Fetter Place in early 2025.
The JJ Mack Building provides 200,611 sq ft of office space across 11 floors, alongside 5,439 sq ft of ground floor retail. It is EPC A rated and is expected to receive a BREEAM Outstanding rating and a NABERS 5* assessment for energy in use.
Hugh Carlson, CEO of Three Crowns, said: “We at Three Crowns are delighted to be relocating to The JJ Mack building in 2025. We look forward to welcoming our colleagues and clients to this sustainable, accessible, and modern workplace.”
Gerald Kaye, chief executive of Helical, added: “The addition of Three Crowns to our tenant roster takes The JJ Mack Building to over 67% let, with strong interest in the remaining space. Coming so soon after we let three floors to J Sainsbury, today’s announcement further highlights the continued strong demand for high quality office space, and the widening gap in the market between best in class properties and the rest.”
Peter Ferrari, chief executive of Ashby Capital, said: “Hot on the heels of our significant letting to J Sainsbury, we are excited to welcome Three Crowns to The JJ Mack Building. This lease demonstrates the building’s sustained appeal and is testament to its high-quality design, strong sustainability credentials, extensive amenities and excellent location. We are confident that Three Crowns will benefit from the step change in quality and lifestyle that their new workplace offers, and we look forward to welcoming further tenants in the coming months.”
Helical and Ashby Capital were advised by CBRE, Knight Frank and Clifford Chance. Three Crowns was advised by Cushman and Wakefield and Bristows.


