London
Nova South, in Victoria, London, is home to the National Cyber Security Centre (NCSC) – part of GCHQ.

The NCSC was established in 2016 to support the UK’s ambition to make the country the safest place to live and do business online, and turns 10 years old in 2026.
Staff at the NCSC work at offices across the UK, but call Nova South their headquarters, offering cyber security support to our critical national infrastructure, the wider public sector as well as industry, SMEs and the general public to help everyone stay safe online.
Working in the capital allows our people to work closely with key intelligence partners like MI5 and SIS, as well as government, law enforcement and academia.
We’ve always maintained a presence in London. Until recently, we occupied a building on Palmer Street, where we secretly resided for 66 years.
MI5 exists to protect the UK from threats to our national security, primarily terrorism and threats posed by states.
More than 5,000 people work at MI5, bringing together people with lots of different backgrounds, and lots of different skills. Everyone at MI5 has the same mission: to keep the country safe.
MI5’s headquarters are at Thames House in central London. We also have several regional offices around the UK, including one in Northern Ireland.
A part of MI5 is the National Protective Security Authority whose mission is to provide physical and personal security advice to help businesses take proportionate steps to protect themselves against national security threats.
The UK’s Secret Intelligence Service (SIS), better known as MI6, are the UK's foreign intelligence service, gathering intelligence and working with partners internationally to protect the UK's interests, values and security overseas, and achieving economic, diplomatic and technological advantage for His Majesty's Government (HMG).