In the late 17th century Ogilby referred to the highway that ran due west from London as the Great Road to Bristol, the nation's most important Atlantic port. However, this changed after Queen Anne began to patronise Bath as a restorative spa. Through the genius of Beau Nash this inland town to the south east of Bristol, grew to be the premier recreational destination for the wealthy and famous during the 18th century. The only practical way to Bath from London was by road and large numbers of private vehicles and public coaches began to travel along what became known as the Bath Road.
The route west from London, through Kensington, Brentford, Hounslow and Slough was over relatively low-lying ground, underlain by London Clay. Along this northern bank of the Thames, minor tributaries such as the Brent and the Coln presented no great barrier to travel. The road was carried over the Thames at Maidenhead where there had been a succession of bridges since medieval times. Beyond this lay Maidenhead Thicket, the notorious haunt of highwaymen. The Bath Road avoids the deeper parts of the Royal Forest of Bray making an easy crossing of the Loddon where it is divided into several branches at Twyford (the twin fords). It then picks a path between the river and the high ground at Woodley to reach the major crossing of the Kennet at Reading.
West of Reading the route follows the low ground of the Kennet river terraces rather than the firmer soils on the high chalk downs to the north. It is not until the road leaves Speenhamland, west of Newbury that it finally reaches the drier chalk downlands that then stretch forward through Wiltshire and the west. In 1691, Celia Fiennes traveling from London to Hampshire observed that From Redding to Veale (Theale) 5 miles sad clay deep way, this is Barkshire; thence to Newbury 8 miles all clay and mirey ground. This illustrates how the combination of wet ground and heavy vehicles had created problems with which individual parish surveyors were unable to deal.
Both coaches and wagons used the Great West Road. A substantial number of clothiers' wagons brought cloth up to London from Wiltshire towns such as Trowbridge and Bradford, and large convoys of clothiers' wains from Gloucester and Worcester blocked the London road through Reading and Colnbrook in the 16th century. Whenever there was a threat of conflict with the Continental Powers, West Country merchants preferred to use road transport rather than coastal shipping and so the volume of commercial carrier traffic varied. Coaches carrying wealthy patrons to the spa at Bath depended on the Western Road and made passenger traffic an important factor on this route. Regular coach services between London and Bath began in 1657 and by the early 18th century large numbers of stagecoach services and private postchaises were traveling between London and Bath. Whereas the petitions to turnpike the Great North Road were based on the damage done by wagons, the case for turnpiking the Bath Road was concerned with the problems of coach travelers. One might speculate that wealthy passengers were more able and prepared to pay for improvements and this may explain why the Bath Road, although not on the worst soils in England, was turnpiked relatively early.
Acts to take tolls for maintenance of the western sections of the Bath Road, around Bath and Calne, had been passed in 1706. Like the improvements on the Great North Road these first turnpikes were administered by local Justices. However, all the turnpikes created subsequently in this area where Trusts, administered by trustees drawn from the local communities. The first section of the Bath Road near London to be turnpiked was over the wet ground beside the Kennet from Reading to Theale. This turnpike, initially to Puntfield in 1714 was later extended on to Speenhamland (Newbury) in 1726. The busy roads between Kensington over Hounslow Heath to Twyford were turnpiked over the following three years. Thus, by 1728 a traveler from London passed sequentially through tollgates administered by the Kensington to Cranford Bridge Trust, Colnbrook Trust, Maidenhead Bridge to Sonning Lane End Trust, Bear Inn, Reading to Speenhamland Trust and Speenhamland to Marlborough Trust.
The first documented evidence for regularly spaced milestones along the Bath Road is a note in the Minutes Book of the Colnbrook Trust, dated 4th Aug 1741. The Surveyor reported that in pursuance of an order made at the last Meeting he Did agree with Thomas Windsor a Stone Mason of Windsor at the Sum of Five Pounds and Eight Shillings per Stone, of the same Dimensions of those placed on the Road from Hyde Park Corner to Cranford Bridge, to be affixed at the End of each Mile from the Stone affixed near Cranford Bridge in the County of Middlesex to Maidenhead Bridge in the County of Bucks, being the Cheapest (amounts he received). And in pursuance of that agreement the said Thomas Windsor has affixed Seven Stones amounting to 16 guineas which he the said Surveyor has bought to account.
Several of these original stones still survive, though the 1741 inscriptions are on the
back face. Either side of Reading there are stones that still carry old
inscriptions from 1742. The original stones from Hounslow through Colnbrook,
Maidenhead and Reading were probably simple square pillars, twenty inches
square. However, during the early 19th century the Trusts had these stones
re-carved into more elegant shapes. The survival of the earlier carving depended on luck as
to which two sides of the stone the mason chose to reshape before making the new
inscriptions. Each Trust chose a slightly different design, those around Colnbrook being
turned into a diamond shape, those between Maidenhead and Reading becoming a triangular
pillar and the slightly younger, 1745, stones around Newbury being recut with side facets. Later in the 19th century
some stones were replaced by cast iron mileposts. Those around Reading were made by
Wilders a local foundry. The replacements nearer London were more variable in design and
have survived least well. Overall, the series of milestones from Hounslow through to Bath
are probably the best-preserved series of well-carved roadside markers in England.