For those unfamiliar with the metric system of measurement, this is equivalent to approximately 75,000 unladen swallows. Provided they are European swallows, of course.
This assumes a 20g swallow. "European swallow" typically refers to the barn swallow, which ranges between 16 to 22g. So between 68,000 and 94,000 unladen swallows.
Heh. So... it can hold 3,000 things that weigh a half-kilogram? Also known as 1,500 kilograms.
What is it with the BBC's hilarious units of comparison? It has clearly become some sort of journalistic inside joke.