Suppose you were inventing, from scratch, a self-financing public postal service. How would you do it? Maybe you'd proceed on the entirely reasonable assumption that you'd charge according to distance. And perhaps you'd get the person on the receiving end to pay the postman before the letter was handed over. No money, no letter.
If you did that you'd be in good company, because that's exactly how things worked in this country for hundreds of years. The rates were complicated (the number of sheets of paper in a letter came into the equation as well as the distance that the letter had to travel) and generated a welter of bureaucracy because every letter had to be logged.
It led to high costs (a letter from London to Edinburgh cost a shilling at a time when many workers earned less than a pound a week) and these escalated as people then refused to accept and pay for letters, or resorted to putting agreed codes on the outside of their letters. The receiver read the code and then rejected the letter.
By the early 19th century, in a Britain increasingly driven by commerce and industry, the antique postal system was simply inadequate.
In the forefront of those who could see this was Rowland Hill, a thinker and reformer who had the ear of government. In 1837 he wrote a pamphlet, Post Office Reform: its Importance and Practicability.
Hill and his followers preached a message that would resonate throughout Britain's industrial growth right to this day - that high volume and efficiency, with bold pricing, will generate more volume and revenue.
Wal-Mart founder Sam Walton would have been proud of him. As Hill saw it, the way forward was to simplify all the postal rates to a basic one penny for a half ounce letter to anywhere in the kingdom.
Then, to cut through the problems of payment on delivery, he advocated pre-payment - the sender would buy an adhesive stamp which showed proof of payment.
Parliament eventually agreed, and the uniform Penny Post began in January 1840. The number of letters carried increased hugely over the next few years - from 76 million in 1839 to 168 million in 1840 and to 347 million in 1850. Add a few more factors - the railways as carriers of the post, growing literacy, improvements in printing, the need for businesses to communicate, increasing job mobility splitting families apart - and it's plain that Hill's foresight was correct.
So, in1840, the pattern was set. Everything afterwards was a matter simply of more and better - travelling sorting offices on the railway, air mail, cheap international rates, automatic sorting, postcodes. Nothing, though, was in the same league as Hill's great leap forward. Significantly, the whole world was quick to follow and within 20 years 85 countries had introduced postage stamps.