The Delaine business has origins that lie back in the 19th century. In 1890 William Smith used a horse and cart owned by his father Bennett to take Bourne folk to and from the Tuesday market in Spalding. Bennett had started in business about 1867 as a general contractor. A fire occurred at their depot in 1907 with sad loss of carts and horses. After William died in 1913 his son Thomas Arthur (1896-1958) married a Miss Emma Weston in 1915 who, through her family connections, brought the Delaine name to the business. Starting with taxis in 1910 Thomas acquired his first motor bus in 1919, PW1558, a 14-seat Ford model T bought for £495. Routes were established to Spalding via Twenty, Grantham via Corby Glen and Stamford via Greatford. In 1923 what was to become the main route from Bourne to Peterborough was started. For some years there was competition from Peterborough Electric Traction all along this route; in 1930 by agreement PET withdrew north of Market Deeping although still serving the road south from there to Peterborough on their route from Spalding.

With a fleet size of five the timetable for March 1928 for 'The Delaine Saloon Buses' showed a Tuesday journey to Spalding for the market, leaving Bourne at 9.45 am and returning from Spalding at 3.00pm. Stamford was served on Fridays, leaving Bourne at 9.45 am via Witham, returning at 2.45pm; an alternative journey left Bourne at 11.15am via Braceboro, returning at 4.00pm. Grantham was served on Saturdays, leaving Bourne at 9.15am and 5.30pm, returning at 3.45pm and 10.30pm. On the route southwards to Peterborough there were 8 journeys from Bourne Market Place to Peterborough Broadway on Wednesdays and Sundays, and 10 journeys on Saturdays; first departure from Bourne 9.00am (10.30am Sundays), last return journey 10.30pm. Subsequently this route terminated at the Cattle Market until Bishops Road bus station opened in 1937. In that same year the single fare from Bourne to Peterborough was 1/3d and the return fare 2/0d. At the time there was also a subsidiary depot in Brook Street, Peterborough, opened in 1932 and closed in 1939; this was primarily established to enable operation of tours and excursions from Peterborough, for which permission had previously been refused because of the distance of dead running to and from the depot at Bourne.

A second disatrous fire occurred at the depot in November 1928 causing much damage and destroying several buses. This meant the cessation of the Grantham service. The business of W H Walpole of Dyke was acquired in 1932 and that of W H Haines of Deeping St James in 1934. A more direct route from Bourne to Stamford via Toft and Essendine came into operation after January 1937 with the takeover of the 'Betterway' service of Thomas Bett of Billingborough from Boston through Billingborough and Bourne to Stamford (the Boston to Bourne section passing to Lincolnshire Road Car, with whom Bett's business had been jointly purchased).  In May 1941 the business became Delaine Coaches Limited. The bus services continued in wartime under often difficult conditions with the addition of workers transport to airfields in the area, including South Witham, Woolfox and North Luffenham.

Over the years the business developed substantially (despite the two depot fires in 1907 and 1928) and has passed down through several generations of the Delaine-Smith family.  The first double-decker bus came in 1948; others were acquired through the 1950s. Delaine was to have experience of a rail replacement bus service in 1951 when the line closed between Bourne and Essendine. A daily bus was put on, running via Thurlby and Braceborough. However it incurred such losses that it was soon cut down to two round trips on Thursdays and Saturdays only, and those only between Bourne and Braceborough. Closure of the M&GN rail line through Bourne in 1959 brought further (mostly short-lived) rail replacement routes, although the last remained until 1999 in truncated form as a Thursday only journey from Greatford to Bourne. In 1961 over 1,100,000 passengers were carried by Delaine, of whom  420,000 were on the Peterborough route (at the time two-hourly in frequency, increased to hourly on Saturday).

The bus station in Bourne opened in 1974 and a town service started in December 1975. An hourly frequency six days a week was introduced on the Peterborough route in 1976.  For a number of years workers contract buses to factories in Stamford and Essendine formed an important part of the business but they declined as factories closed and the last such operation ended in December 1988. Route numbers were introduced in 1992. In 1993 the first vintage bus running day was held in Bourne. Mr Hugh Delaine-Smith (1920-1995) joined the business after leaving school in 1938, the son of Thomas Arthur and father of current Managing Director Anthony. Hugh was awarded the MBE for services to public transport in the New Year Honours List for 1995; sadly he died just two months later in March. The company name Delaine Buses Limited was adopted in 1995 and the company's first low floor bus was acquired in 2000, a Volvo B7TL double-decker registration X7OCT.		A cameo of the then fourteen vehicle Delaine fleet as it was in 1963 comes through information found in an article by David Kaye in a back number of Commercial Motor magazine, with six coaches, five deckers and three dual purpose saloons. KTL780 (45) and RCT3 (50) are still part of the Delaine heritage fleet in 2019.

In 2006 the fleet size was recorded as twenty four, of which no less than eighteen were double-deckers. The sixth generation of the family came into the business when Jennifer (great-great-granddaughter of Thomas) joined the firm. The Delaine fleet in summer 2012 numbered twenty one vehicles - of which sixteen were double-deckers, some of which carried names. In 2015 the fleet size was twenty seven, many carrying DBL registrations. All are of Volvo manufacture and nineteen are double-deckers - plus another three Leyland double-deckers in the heritage fleet (the museum to house them opened in spring 2019).

Changes from mid-January 2016 saw routes 201 and 202 combined to give a through bus every hour on the Bourne - Stamford - Peterborough route, also improving connections within and across the town of Stamford. October 2018 saw the addition of a new route 205 between Stamford and Peterborough via Wittering and Wansford, replacing Centrebus route 9 (who had acquired the Kimes business in 2011). This meant that Delaine was now operating both of the traditional routes between Stamford and Peterborough that in days gone by had been the preserve of their friendly rivals at Cream Bus. January 2019 saw service 203 from Stamford to the Deepings extended onwards to Spalding, creating a new connection across the county. Current 2019 fleet size is thirty, all Volvo chassis, comprising twenty three double-deckers and seven single-deckers (the latter primarily used on the Stamford routes). Sunday is the quietest day with just two vehicles out working the 101 to Peterborough hourly.

and incorporating information from articles and publications by

A L Baker, Peter Moore, David Kaye and Anthony Delaine-Smith

found in the libraries of Lincolnshire.