This is a super article from the Hendon and District Archaeological Society's Newsletter March 1974, which they have put on their wonderful website:
History of Field Drainage
One exhibit now on show at Church Farm House Museum deals with field drains as an aid to archaeological dating. The following notes are a background to the subject:
Land drainage has a long history in Britain, going back to the Roman cutting of the Car Dykes in the Fens and the ditches of Romney Marsh. By the late eighteenth and nineteenth centuries, however, most available land had already been reclaimed by surface draining of lakes, marshes and fens. At the same time there came the Industrial Revolution and a steady rise in population. Early statistician Gregory King estimated the population of England and Wales at 5 1/2 million in 1700. By the first Census in 1801 it was 9,000,000 and by 1851 almost 18,000,000. The problem was how to provide food for all these people, using only the same amount of agricultural land as before.One solution -- there were of course others -- was to improve the drainage, and thus the crop-yield, of heavy farmland by underground, or hollow, drainage. This was no new idea. Deep trenching, with faggots, stones, shells or gravel laid at the bottom of the trench, and then the earth by replaced on top, had long been used as a drainage method; such drains, however, did not last long and needed frequent or re-laying.
Towards the end of the eighteenth century a few landowners began to employ a more effective type of although drainage, using tiles or drain bricks to replace the faggots and stones. One method was to cut a small, rectangular channel at the base of the trench, and put a roofing tile over it. Another was to lay two hollowed-out bricks face to face so that the hollow formed a pipe. A later improvement was to turn over the edges of a roof-tile into a horseshoe shape before firing; this was either laid directly on the floor of the trench or on a base plate. It is this original use of roof tiles for drainage purposes which gave later land drains their name: tile-pipes.
As a mark of the importance of the government placed on the laying of hollow drainage systems, a statute of 1826 (confirmed in 1839 and 1840) exempted from the duty normally paid between 1784-1850 on bricks and tiles "those bricks made solely for draining wet and marshy land -- provided they are legibly stamped in making with the word DRAIN."
The late eighteenth or early nineteenth century methods were expensive, and only rich landowners could afford them. Early tile-pipes were shaped by hand around a drum. It was not until the mid-nineteenth century, when the extrusion method of machine-making tile-pipes was invented, that hollow drainage by tile-pipe came within the reach of most farmers. Thomas Scragg patented a cheaper method of making tile-pipes in 1845; by 1849 a writer in the Journal of the Royal Agricultural Society of England could describe a machine for making drain tiles operated by one man and three boys, who could turn out nearly 11,000 tiles off 1" bore in ten hours. The price of this machine was £25.
Once cheap tile-pipes became available, they were widely used. At first pipes of small 1" bore were tried. The theory was that the water would be channelled through these so fast it would prevent silting. In fact the result was the opposite: the pipes were so narrow they silted up.
A large bore pipe -- first of 2 in., later of 3 in. or more -- came into use, and systems were laid up to the 1890s. Then, with the start of the period of agricultural depression, no more tile-pipe drainage was laid, virtually until 1939. Mole-drainage (cheaper, although it had to be renewed) was used instead.
I found that the Rural History Centre University of Reading website had the Scraggs machine on it so put in the links, and it also has a list of other brick and tile making machines.