MI6 bosses were left red-faced after closing a top-secret spy base when details of the location were accidentally leaked.
The training centre based in central London had been used to teach agents spycraft and self-defence for many years, but the location, floor plans and planning documents of the facilities were published by the local council.
The planning documents revealed the costly additions to the building, which included CCTV cameras, high-tech security gates and satellite dishes.
The venue is now empty as Secret Intelligence Service (SIS) officers were relocated to another site.
It is understood that MI6, which has its headquarters in Vauxhall, London, decided to vacate the spy school building, believed to be in Westminster, for strategy and not security concerns.
Neighbours had previously complained about "electromagnetic interference" from the building, which affected their TVs and radios, reports the Mail on Sunday.
Documents show that MI6 got a telling off from Westminster planning chiefs after the satellite dishes were installed without permission 'knowing that Government departments are immune'.
Detailed plans for the spy training centre in central London have been accessible online since 2004 - when SIS officers were still using the base regularly. Another request, from 2017, referred to the spy centre as 'Government offices'.
The latest hiccup comes after spy chiefs were rapped by furious MPs and peers just before Christmas for missing key deadlines to provide evidence to Parliament. The Intelligence and Security Committee, which oversees MI5, MI6 and GCHQ, lashed out at agency bosses for delays in responding to requests.
Publishing its latest 56-page annual report, it said: “The committee has been severely hampered over the past year by the failure of the UK intelligence community to meet standard deadlines as part of the ISC inquiry process.
“In the committee’s annual report 2019–2021, we attributed this to their reduced resources during the pandemic and their need to focus on immediate national security threats.
“However, this is no longer a credible explanation. This is a very serious issue, as it prevents the committee from effectively performing its statutory oversight role."
