Reading it, he sees that it concerns British nuclear secrets, and he realises that he has been a patsy. Instead of smuggling glass-making secrets out of Prague, Cunliffe is using Nicolas as a courier to smuggle British nuclear secrets out of England. On the second trip, Nicolas left the wrong Norstrund in the glass factory, which was empty.
He reads that it involves British nuclear secrets and realizes he's been tricked. Instead of smuggling glassmaking secrets out of Prague, Cunliffe is using Nicolas as a courier for British nuclear secrets leaving England. On the second trip, Nicolas delivered the wrong Norstrund to the factory, which was empty.