I learn from the Guardian that after the postal prices change next week, if the sender gets the postage wrong then the addressee will be fined £1 plus the full cost of the postage (not the difference). I.e. if I put 32p on a light, A4 letter, the recipient gets a fine of £1.44
Quite apart from the issue that the postage has been paid twice, the fine is levied upon the person who had no hand in the error.
If I send a heavy item which should have £10 postage, but put £9.50 on it, the fine would be £11 under these rules, not £1.50 as might be deemed 'fair' (though it's still paid by the addressee), or 50p as it would be now (the difference is currently paid).
This means that the item costing £10 to post, with £9.50 postage on it will see a revenue to the post office of £20.50!
I wonder how long it'll be before anti-junk mail campaigns take note of this, and use the fine to punish the junk mail companies?
'Return to sender' may be happening a fair bit.