The top secret mission to deliver a portable secure phone to Margaret Thatcher

The device was the world’s first portable secure phone, housed inside an ‘executive-style’ briefcase. Called a Brahms phone, it was used to provide vital intelligence and secure communication from No10 to the battlefield in the Falklands conflict – which ended forty years ago in June 1982.

Mike, a retired intelligence officer, assembled the gadget at GCHQ using ‘voice coder’ technology, spare radio parts and a briefcase he purchased from a department store on Cheltenham promenade. In August 1980 Mike travelled to Switzerland, where Thatcher was staying on holiday with Sir Douglas Glover, to install the device for its first international call.

“I flew to Geneva with the Brahms sitting next to me on the seat,” 78-year-old Mike said. “I was the Queen’s messenger, first on and first off. The Swiss police even offered me a handgun, but I declined that offer. I installed the Brahms in a room that was to be used as the No10 office. The Prime Minister came round to talk to everyone and said to me ‘I know why you’re here.’”

The Brahms used the public phone network system and was encrypted using a daily changing key supplied by paper tape. Mike, who worked at GCHQ for 37 years, said the device also had ‘Emergency Destruction Instructions’, which advised the operator to burn the key tapes. “And if that’s not possible,” Mike said, “then you can eat it at the last resort.”

GCHQ Historian, David Abrutat, said: “Mike’s story is just one example of GCHQ’s brilliant people staying one step ahead of adversaries and keeping the UK safe. GCHQ played a vital role in the Falklands conflict, producing 90% of the intelligence, and it fundamentally shaped the organisation’s role in supporting the military right up to the present day. As we approach the 40th anniversary of the end of the Falklands conflict, we remember the sacrifice of those who fought on the front line and reflect on the tragic loss of life on both sides.”