Jet! When Britain Ruled the Skies2012

[Lord Tebbit points to a large handle on the ceiling of the cockpit in a Bristol Britannia]

Lord Tebbit:
It was the first really very, very electrical aeroplane. But that had a downside, of course, in that if you lost the electrics you were in real big trouble. That's when this switch came in. And basically it would disconnect all the generators and then reconnect them again. And you should get at least *some* of your electrical services back again. It was known, inevitably, as the Jesus Christ switch, because that was the only occasion when you'd use it, at that moment when everybody on the flight desk was saying "Jesus Christ!". And you'd grab it and hopefully all power would be restored. Very useful!