Hay said: “The start of construction is an important moment for Cheltenham and for Gloucestershire and demonstrates our commitment to creating an internationally recognised development that will deliver lasting benefits for the local, regional and national economy.
“This is a nationally significant development, but its impact will be felt very locally.
“Golden Valley is about creating opportunity for local people through new jobs, affordable homes, school programmes, skills partnerships and initiatives such as the recently launched University of Gloucestershire’s Golden Valley scholarship.
“We want more people across the county to see a future for themselves in cyber, technology and innovation.”
Dr Marsha Quallo-Wright, GCHQ director of technology futures, said she looked forward to working alongside academics and the wider cyber industry to address “emerging security challenges”.
“These collaborations will play an important role in supporting our mission to keep the UK safe,” she said.
Phase one is expected to have been completed in early 2028.