The Africa Centre is seeking a design team for works to upgrade the charity's Great Suffolk Street premises.
Architects tendering for the project are invited "to develop a bold and creative design concept that embraces the aesthetic and cultural diversity of the African continent and its diaspora and reflects a contemporary pan-African vision".
Interested firms are invited to express interest to project managers Cambridge CM, after which a longlist of participants will be selected to proceed to the next stage in the process.
"The redesign of Gunpowder House opens the next chapter in the story of The Africa Centre," said Kenneth Olumuyiwa Tharp CBE, director of The Africa Centre.
"We're really excited to see how designers and architects rise to both the challenges and opportunities of designing a pan-African centre for the 21st century.
"It's so important that members of our community have a place that they can call home; our central aim is to become the most welcoming cultural hub in London."
Last December the Mayor of London's Good Growth Fund awarded £1.6 million towards the project.
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