Auf Wiedersehen, Pet (1983)

S1E4 Suspicion

An expensive item disappears from the hut, leading everyone to distrust one another. In an effort to identify the thief, they devise several schemes, but, as is often the case, each one fails miserably. Ultimately, they discover that the real culprit isn't any of them; instead, it's someone from outside the hut who is responsible for the theft.