This was broadcast exactly 2 years prior to the real terrorist attacks on London.
The Prime Minister and Cabinet were said to be relocating to TURNSTILE, a bunker in the Cotswolds. The Central Government War Headquarters, also known as TURNSTILE, was ironically decommissioned only 4 months after this episode went to air.
When JJ is walking outside after Denton tells him to "show them the magic" it is in the same courtyard as where Rose Tyler lives in Doctor Who (2005). You can see her building behind him and where the TARDIS should be on his left (viewer right).