Scientists at top secret monitoring base GCHQ were left a little sheepish when they realised a mystery transmission that had been baffling them was a randy ram, it emerged today.

The strange high-frequency noises, coming from the Scarborough signal station on Irton Moor, North Yorkshire, had been confusing staff for a number of days.

But, as reported in GCHQ's in-house paper the Daily Observer, the weird noises were traced to a rampant ram rubbing itself against an aerial mast.

The article said the noises were unlike anything staff had encountered before and the investigating team initially feared they were coming from spies or aliens.

Their investigation found the signal only happened in the day time, went across all the high-frequency bands and only Scarborough aerials could pick it up.

''Exhaustive tests'' revealed that the signal came from one antenna in particular and ultimately found the answer: ''a horny ram''.

The article read: ''In between servicing some local ewes it was partial to rubbing its horns against the aerial masts.''

GCHQ spokesman Bob McNally said: ''It was probably some ritualistic thing, like marking a notch after a conquest. It's possible the ram was attracted to the mast which may have given off some kind of tingling sensation, but it was probably just a post to rub against.''

He said the article featured in the ''Weird but True'' section of the Cheltenham-based GCHQ's internal newspaper.