MEMORIES never fade of taking the terrifying walk over the divide that once existed between East and West Germany .

Trigger-ready guards at your back; trigger-ready guards ahead. 

One wrong move, however innocent or accidental, and . . .

It didn’t bear thinking about. But, nevertheless, you did. Think about it. Every step of the way; and beyond, always looking for followers, watchers, anyone whose presence could be queried.

The brain made a rapid recall of all those stories of would-be escapists from the East who failed to make it across the desolate divide.

Those who had been dragged back, often wounded, sometimes dead. And the pictures that went around the world of a young man, tangled in barbed wire, left to bleed out because no one dared go to his aid.

And another of a Russian soldier making a desperate running jump over coils of  that same fearsome wire – a triumphant leap to freedom.

The mind wouldn’t change channels, switch to more calming and mundane thoughts. The location and its history were too confronting, writ too large to ignore.

So you set out, not daring to look back.

Past the sign warning “You are now leaving the American sector” with its low-key guardhouse, scarcely more than a king-size garden shed.

Now to walk the three hundred metres of cleared and deserted street to the East’s larger, more grandiose and frightening counterpart.

To be checked and questioned by cold-eyed, humourless soldiers to whom one imagined a smile or a friendly “Hi” would be akin to treason.

Little wonder that the frisson, bordering on fear and impossible to override back then, quickly surfaced as I lost myself in reading The Berlin Exchange, the latest in an exceptional series of espionage thrillers by Joseph Kanon. 

This is the Cold War, doubly chilled. Set with the notorious wall now well and truly in place. A tale of intrigue, deception and double-dealing fresh from the freezer. With the barrier between east and west firmly at its core.

As ever with Kanon, the writing is diamond bright. Brittle and sparkling. A story that is heavy with dialogue, conversations full of hidden meanings, rippling with undercurrents that take time to interpret – and even then, leaving you uncertain that you have the full gist.

Words batted to and fro, trying to score points or decipher their meaning.

The story swirls around Martin Keller, an American recently released from a British prison to be part of a spy swap across the East-West German border. He knows few of the details – whether the exchange is a deal done with Russia’s KGB or, as he hopes, the East Germans.

He yearns for it to be the latter,  which brings propsects of  a reunion with his former wife, Sabine, and their now teenage son. Even if they are now living with Kurt Thiele, the man she has married and  into whose hands Martin is delivered.

The exchange gets off to a bad start.

There’s a shoot-out as a stolen ambulance tries to crash through the barrier. Shots fired from the ambulance and by the German border guards.  The ambulance driver is dead, his passenger dragged away, wounded.

From then on it is a relentless mounting of tension as events convince Martin the shots fired at the border were meant for him.

He reconnects with the welcoming Sabine, establishes a mutually firm relationship with his son, a rising teenage star of a daily TV propaganda soap, and shows acceptance of  the often baffling “arrangements” that Kurt has made for him.

And all the while nothing quite fits, or arrangments are suddenly changed and doubts are cast.

Martin discovers Kurt’s role as an official “fixer” has dubious offshoots.

His ex-wife’s ill health deteriorates, loyalties are questioned and tested.

And all the while, the tension mounts.

There’s no fast and furious headlong action but a ceaseless weaving of a web of deceit and double-dealing.

Gripping, nail-biting and relentless as it twists and turns towards a tragic finale back where it all began – at that frightening gap in the Wall where East once faced off again West.

Where memories are forged that can never be erased.

The Berlin Exchange (Simon & Schuster, paperback £8.99)