The imposing sandstone terrace on the eastern side of the Deepdale Enclosure in Deepdale Road, Preston, is unmistakeably named Stephenson Terrace: the name being prominently emblazoned in a panel set high up at the centre of the row. What is almost certainly wrong, however, is to associate the name with the famous father and son railway engineers.
The mistake has persisted from its first occurrence in Charles Hardwick’s History of Preston, published in 1857, shortly after the terrace was completed in 1850:
Stephenson Terrace, Deepdale-road, or rather the open space in front of it, might be considered a public ‘square’, but for the triangular form of the enclosed and planted area. … This area was judiciously enclosed, and the neat lodge at the southern corner erected by the corporation, in the year 1850. … The handsome stone terrace was erected by Mr. George Mould, contractor, and named after the celebrated engineer. [Emphasis added] 
Hardwick was correct in identifying George Mould as the builder, but if by ‘the celebrated engineer’ he intended George Stephenson, who had recently died, or his son, Robert, then he was probably mistaken.
The terrace is instead almost certainly named for John Stephenson, the brother-in-law of George Mould, as is made clear in Mannex’s trade directory for the town published in 1851:
Stephenson terrace is a superb line of buildings, on the east side of Deepdale road, immediately opposite East View. This magniﬁcent Grecian terrace is the property of George Mould, Esq., civil engineer, and was erected by him in 1849-50 on land purchased from the corporation of Preston. The dwellings are 24 in number, and the four in the centre projection are three stories high, as are also the north and south wing of two houses each. The whole at ﬁrst sight has a picturesque appearance, and presents to the beholder ‘uniformity and elegance combined’. The vestibule to the front of each building is embellished with two columns and parapets, and the gardens, pallisading, and gateways, give them the appearance of the villas at Venice. On the entablature in the centre parapet is cut in alto relieve, the words, ‘Stephenson Terrace’, the buildings being dedicated to the late John Stephenson, Esq. who was brother-in-law to the proprietor. The length of the terrace is 424 feet, and the fronts of all the houses are of Longridge stone. The piece of land opposite is a triangular area enclosed and pallisaded, which is intended to form a plantation. At the south end of this open area is a neat cottage for the residence of a policeman to protect this delightful spot. [Emphasis added] 
When this description appeared, ‘Mannex & Co., publishers of county & district histories and directories’ had an office nearby at 12 St Ignatius Square.  The staff would have witnessed the building of the terrace, and they would probably have been acquainted with George Mould. The description of the terrace and the identification of John Stephenson were repeated in subsequent Mannex directories; if the identification was wrong then surely George Mould or others with local knowledge would have obtained a correction. Hardwick must have been unaware of the entry, or have discounted it.
In fact, John Stephenson (1794-1848) was himself a celebrated railway engineer. Although no relation to George Stephenson, he worked with him on the Stockton & Darlington Railway in 1824, he himself going on to become one of the country’s leading railway contractors. He was regarded as the man on whose advice George Stephenson had relied greatly since the construction of the earliest portions of the Stockton & Darlington Railway. 
Grace’s Guide to British Industrial Industry supplies the following: John Stephenson ‘introduced scientific methods into earthwork construction and the excavation of deep cuttings’. He was one of the principal engineers in the construction of ‘the whole of the lines from Lancaster to Edinburgh and Glasgow … with their numerous tributary branches and extensions, the Scottish Central to Perth, and the Scottish Midland to Forfar’. 
George Mould would have started work on Stephenson Terrace shortly after his brother-in-law’s death and so the naming provided a fitting memorial. The two men had worked closely together for a number of years with John Stephenson as the railway contractor and George Mould as his manager, engaging in very sizeable and complicated undertakings, as is shown in the following newspaper notice:
Bolton and Preston Railway. Notice is hereby given that, about 2 o’clock in the afternoon of Tuesday the 16th 1842 a mob gathered on the works of the railway at Chorley and compelled the workmen employed there and in the service of Mr John Stephenson, the contractor, to leave their work. On the morning of Friday the 19th instant the workmen again attended at the railway works, and had an interview with Mr Mould, Mr Stephenson’s manager; at which interview they made certain requests in connection with their future work, with which requests Mr Mould at once avowed himself willing to comply. That the men cheered and stated themselves to be perfectly satisfied; but they requested a further favour that they might be allowed until this day, Monday the 22nd instant before they resumed work, with which additional request Mr Mould complied. That in the course of an hour after the interview above referred to Mr Mould received a note containing what purported to be a resolution of a meeting of the men, demanding as a further condition of their resuming work an advance of wages. That Mr Mould declined to comply with this new demand, the wages paid by him to efficient workmen being more than the full average rate of wages to parties similarly employed. That the work people have consequently refused to return to their employment and the works of the railway continue at a stand.
Notice is therefore hereby given that five hundred workmen are now wanted for the purpose of the above works; and that good labourers may meet with employment there at a rate of three shillings per day wages for ten and a half hours’ work. None but experienced workmen need offer themselves; and to those who may be engaged 2s 6d will be allowed as travelling expenses to the works. (Manchester Guardian, 24 August 1842). [Emphasis added] 
This was the time when the railway mania was reaching its peak, and in 1846 the Fleetwood, Preston and West Riding Railway company had been established to provide a rail link between Lancashire and Yorkshire, utilising the existing Preston and Wyre and Preston and Longridge lines, which would be linked by the ‘Miley Tunnel’ from Deepdale to Maudland. George Mould’s tender of £69,500 was accepted for the construction of the link, and work started the following year. The Preston and Longridge Railway Company had built a tramway in 1840, linking the newly opened Tootle Heights Quarry at Dilworth to a station at Deepdale. The terminus for this line was directly behind where Stephenson Terrace now stands. The line facilitated the economical use of Longridge stone in the construction of Fulwood Barracks, in the Victorian reconstruction Preston Prison … and in the building of Stephenson Terrace. For more information, the best guide to the history and development of the Preston and Longridge Railway is David Hindle’s All Stations to Longridge. 
The easy access to Longridge sandstone resulted in its being the choice of material in the construction of houses as Deepdale Road extended northwards and the Deepdale enclosure was completed, and then throughout the town.
Before the arrival of the railway (which also played a key role in the development of the Dixon family’s Frenchwood Tannery), brick was the favoured building material, beginning in the 17th century when gentry families such as the Molyneuxs were angering the town’s burgesses by digging clay on Preston Moor. For more information put the word ‘brick’ in the search box on David Berry’s excellent Preston Court Leet records site.  The clay pits can clearly be seen on Lang’s 1774 plan of Preston, and the adjoining field is there named Brick Kiln Croft. Barton Terrace, which was built alongside that field directly south of Stephenson Terrace and shortly before the arrival of the railway and cheap Longridge stone, is constructed of brick. See also the articles on Preston Moor and the Lang plan on this site.
The above would seem to clearly establish the accuracy of the account in the Mannex directory and discredit that supplied by Charles Hardwick. Yet it is the latter’s that has persisted and now features in the many popular books which regularly repackage the town’s history. For example, in Keith Johnson’s Preston in 50 Buildings:
On the east side of Deepdale Road, opposite the Deepdale Enclosure, built between 1847 and 1850, stands a fine line of town houses. The stone terrace was erected by contractor George Mould and named after the celebrated railway engineer George Stephenson. By then, Stephenson had the construction of the Preston and Longridge railway tunnel in hand, which is now known as Miley Tunnel and runs under the west side of the town – from the Deepdale terminus to Maudland. The fact that the railway terminated originally at the rear of Stephenson Terrace was a contributing factor in the choice of name, which is displayed in the stonework in the centre of the terrace. [Emphasis added] 
George Stephenson had, in fact, settled into semi-retirement by the 1840s and was dead by 1848.
John Bannister, in Chapter 3 of his The Street Names of Preston, wrote, ‘Stephenson Terrace was erected by George Mould and named after George Stephenson the locomotive engineer – the name being suggested by the newly-built railway behind the Terrace.’
And when Preston Council commissioned an appraisal of the site in 2008 the authors continued the attribution to George Stephenson:
By 1849 there are houses all along the east side of Deepdale Road; the buildings above the junction with Deepdale Street are Stephenson’s Terrace. The list description [which gives the terrace a grade 2 listing] states that these houses were built c.1847-51 but the map evidence would seem to indicate that 1847-9 is more likely to be the correct date. … The terrace was built by a local contractor, George Mould, and named after the famous engineer, George Stephenson. 
Additionally, they list Stephen Sartin’s A Tour of Edwardian Preston as a source, and I seem to remember that in that publication he writes that the terrace was named for George Mould’s brother-in-law, (although he gives no reference). Also, the authors are wrong to place reliance on the early OS maps for dating; the rapid spread of the railways led to revisions to incorporate developments around railway sites. For example, the Lancashire LXI 6 in sheet which includes Preston, surveyed between 1844 and 1847 and published: in 1849, which can be found on the National Library of Scotland website (https://maps.nls.uk/view/102343946), shows Maudland Station, yet that station did not open until 1856 ( See Wikipedia: https://en.wikipedia.org/w/index.php?title=Maudland_Bridge_railway_station&oldid=821739510.
Nigel Morgan, who was responsible for hundreds of listings, always started his investigation of an area by examining the first OS maps and would have been aware of the revisions. Nigel recognised that George Mould had named the terrace after his brother-in-law: he mentions the fact in one of his unpublished works, but he, too, supplied no reference.
It would perhaps be possible to take a post-modernist position and argue that since the ‘George Stephenson’ attribution has held sway for so long then it has acquired its own ‘truth’. But as with so much post-modernism that will not hold water: George Mould was commemorating the Stephenson who was his brother-in-law and with whom he worked closely for many years.