John Hopkins

He waits for the driver to get moving again, but just as he's sitting back and thinking of home, another car pulls alongside him.

The doors on both sides of the car are flung open, and Riley is hauled bodily from the vehicle by three burly officers of the Russian security services.

Cold steel closes around his wrists, locking his arms together.

He's bundled into their car, which accelerates away from the border and back down the road towards the interior.

Riley sits in the back as the cold, inevitable realization dawns that his friends in the trust group were secret police all along.

It was nothing more than an elaborate trap, and he, Sidney Riley, the great manipulator, walked right into it.

At the time of his arrest, the Russians believe they have caught the master spy who has slipped their grasp before.

Worried that his connections in MI6 will send more agents to look for him if it turns out he has been taken in Russia, they put out a story that a couple of Westerners have been shot crossing the border.

In reality, he is taken to the Lubyanka, where he is interrogated for weeks.

Sadly for Riley, his time is up.

Britton does not ride to his rescue.

And on the 25th of November, 1925, he is driven out to some woods where he is executed.

There is no formal announcement of his execution.

Sidney Riley simply disappears.

It will be decades before the Cold War thaws and documents get declassified that explain the truth.

But eventually, something resembling a clearer story emerges.

Of his life, his operations for military intelligence, his arrest, interrogation, complete with those scribbled notes on cigarette papers, and his death.

In the intervening years, without confirmation of his demise, rumors begin to build.

Some claim he has escaped again.

Others insist he is still operating somewhere in Europe under yet another name.