GETTY David Davis is carrying a hi-tech Faraday briefcase to conceal Brexit secrets

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The Brexit Secretary has been photographed carrying the silver 'Faraday briefcase' – which blocks all wireless, cellular GPS and WiFi signals. A friend of Mr Davis who served as a former special forces soldier disclosed the special arrangements to the Telegraph.

Brexit talks 2017: Day one of Brexit negotiations latest pictures Mon, June 19, 2017 The first stage of the negotiations concerns the fate of European expatriates in the United Kingdom and Britons settled in Europe Play slideshow EPA 1 of 11 David Davis and Michel Barnier give a press conference at the end of a meeting at EU Commission in Brussels

The briefcase is based on the Faraday cage, a secure box invented by English scientist Michael Faraday in 1846 to block electromagnetic fields. Mr Davis has also swapped his Apple Watch for a Garmin timepiece amid fears foreign spies could activate the microphone on the device and listen in to meetings. Spies have been known to go to extreme lengths to protect their security in the age of the smartphone, with some placing their mobile phones in fridges to block radio signals and stop intelligence agencies listening in on conversations.

The news of Mr Davis’ sophisticated Brexit briefcase comes as he prepares to fly to Brussels next week amid tense negotiations over Britain's evacuation from the EU bloc. He will meet the European Union’s chief Brexit negotiator Michel Barnier on Monday to discuss Britain’s 'divorce bill' and the rights of EU nationals after Brexit.

GETTY Labour MP Stephen Kinnock, left, speaks to journalists

GETTY Michel Barnier and David Davis are set to disagree on various terms of the Brexit negotiations