Blake's 7, Series Four

Orac:
Random fluctuations in circuit pulses.

Avon:
Cause?

Orac:
External influence.

Tarrant:
[Over comm from Scorpio] We've nothing visible on the detectors or the scanners.

Dayna:
Could they be faulty?

Orac:
Detector and Scanner circuits record normal function.

Avon:
So how is it external?

Dayna:
A freak magnetic storm?

Orac:
That would have been observed.

Vila:
[Over comm from Scorpio, panicked] So what have you observed?

Orac:
A paradox.

Avon:
In other words, nothing.

Orac:
Correction: the pulse influences are external to the circuits, but could be internal to the craft.

[Avon punches a switch]

Avon:
Tarrant, what have you got up there apart from yourself, a half-wit and a corpse?

Tarrant:
A box.