This activity was invented in 1854 by a Dartmoor guide who left a bottle at a beauty spot and asked walkers to leave cards in it. Today there are an estimated 4,000 letterboxes, hidden throughout the moor, the locations passed on by word of mouth. Each one has its own ink stamp, and at any time a small army of collectors criss-crosses the moor to mark their pocket books. Now, the RSPB and the National Park have asked them to stop for three months because this trivial pursuit is disturbing the nests of rare breeds such as golden plovers.
"They sometimes spend a long time in one area, rummaging in places where people would not normally go," Gillian Taylor of Dartmoor National Park said. "This can prove fatal to the young of ground-nesting birds."
Finally, spare a thought for a man from Beauly, Inverness, fined pounds 200 this week. His crime? Catching a salmon on a Sunday.