“Good morning, Mrs Goggins,” said Postman Pat in his cheerful way as he did every morning. Mrs Goggins, on the other hand, did not seem her usual self at all, distinctly frazzled in fact. Perhaps it was the queue, Pat thought; he had never seen so many rather cross-looking customers packed into Greendale’s post office shop.

“Oh Pat,” she exclaimed. “I’m in a terrible pickle. I cannot make head or tail of this pricing-in-proportion scheme the Royal Mail’s brought in.” She sobbed and reached across a pile of odd-sized envelopes for the Valium.

“Now, now Mrs Goggins,” Pat said soothingly, discreetly moving all sharp objects away from her, “it can’t be that bad. Though come to think, Mrs Peet practically spat at me today, most unlike her. What’s it all about, then?”

“Well, Pat,” spluttered Mrs Goggins, “for the past, well, 166 years or so, the Post Office has charged for everything by weight, but some genius up top says I now have to charge by size as well. A basic letter is only a basic letter if it weighs under 100 grams, whatever they are, and is less than 24cm long, 16.5cm wide and 0.5cm thick.”

“That does sound complicated,” Pat responded sympathetically, carefully removing the ball of string that Mrs Goggins had somehow contorted into the shape of a noose, “but what does it really mean in practice?” “It means”, Mrs Goggins declared, slightly hysterically, “that if Ted Glenn sends out his monthly A4 sheet Greendale Farmers Gazette without remembering to fold it we have to charge him extra because it counts as a large letter and he won’t like that.” “Oh”, mused Pat, “well, I’m going.” “Where?” asked Mrs Goggins. “To become a milkman,” Pat declared.