I was Hess's guard in Spandau and I can't believe he flew to Scotland without his Führer's approval

I was a captain when I guarded him at Spandau in the 1970s and later the commanding officer of the Kings Own Scottish Borderers, and responsible for demolishing the prison in 1987 after his death.

Later, when I was chief inspector of prisons in Scotland, I inspected Dungavel after it became a prison - but originally it was the house that Hess had been heading for, so in some way for many years, Hess has been part of my life. Because of this, I have had a keen interest in his flight and the details of it.

My thoughts are that I can't believe that Hess was acting alone. I find it implausible that he loaded a Messerschmit with two additional fuel drop tanks then flew from the bottom end of Germany, across German airspace unchallenged, then across the North Sea, and into British airspace without any challenges about what he was doing.

How did he managed to carry out such a complicated and involved mission without a higher authority being involved?

I don't think the flight was something he could have organised himself; someone, or a number of people, would have had to have been complicit. I can't see how Hitler wouldn't have known what his deputy was doing that day.

• Clive Fairweather is a former SAS commander and chief inspector of prisons in Scotland.