At the headquarters of the HM Stationery Office Press, 3,430 reels of printing paper are ordered to print the new L-Z edition of the London Telephone Directory. This adds up to 5,000 miles of paper per issue, and with four issues a year that's enough paper to circle the globe.

Each reel contains a mile and a half of paper, and the reels are replaced every half an hour, with print workers joining the new reel to the old one, tearing off the loose overlap. Each year's output requires 56 tons of ink, enough to fill a swimming pool.

Each volume comprises 22 sections. A machine prints an individual section. It has four drums, each of which has the type for sixteen pages fixed round it, adding up to 64 pages. The printed paper is cut into four strips, which are collected, cut up and folded so that the pages are in correct order. Complete sections are made at the rate of 300 a minute, and bundled in an electric bundler.

The bundles of completed sections to to the assembly department, each identified by the distinguishing mark on the back edge. A machine with 22 arms simultaneously works on 22 copies, placing them on a moving belt and adding each successive section. The black markings on the unbound spine form a straight line, so that a checker can ensure that everything is in the right order.

The books are then trimmed, the spine glued, and rectangles of open-wove cloth are pressed against it prior to the application of the cover. Breaker plates make creases in the cover so that they take on the shape of the book.

The finished directories then have advertisement labels stuck on by hand, with skilled workers able to apply 90 a minute. The directories are then trimmed by a guillotine, three at a time, 3,000 pages a stroke. Every four hours, the blades have to be changed for resharpening. Finally, advertisements are printed on the spine (thick enough to make this viable), and the directories are ready for distribution, bound into bundles of eight for convenient shipping.

7,000 tons of directories per year are produced by the factory, and the volume is increasing all the time as more people become connected to the telephone. At present rates, it is estimated that the directory will have to come in three volumes by 1942. In 1878, there were just eight pages of names and nine pages of testimonials, sent out to 200 subscribers. Nearly sixty years on, 2,500 pages are sent to 850,000 subscribers.