3803 was completed at the Great Western Railway’s Swindon factory in January 1939 at a cost of £4,285, including £1,147 for the boiler. (The cost of the tender is recorded as being £1884, but it was coupled with 1923-built tender no 2218 when completed, which would have cost around £1,000 when new.) The GWR at the time was hoping for a large share in a probable Government grant for building new engines for the war effort at the outbreak of the war, which had formerly been intended for the GPO, and this is thought to have accounted for the unusual price of the tender.
3803 took part in the 1948 Locomotive Exchange Trials where it performed well against LMS 8F and WD Austerity 2-8-0 and 2-10-0 locomotives. It is believed that the GWR bored out the cylinders before the trials to improve its performance.
The 2800 and 2884 classes were only displaced when the BR Standard class 9F locomotives were introduced in 1954 although members of the class survived in service until 1965.
3803 spent most of its time plodding around the GWR system on heavy freight trains, being shedded first at Tyseley, then Banbury.
BR motive power depot allocations since 1948.
| Date Arrived | Depot |
| January 1948 | Banbury |
| June 1948 | Old Oak Common |
| February 1949 | Southall |
| May 1952 | Cardiff Canton |
| August 1958 | Llanelly |
| March 1959 | Gloucester |
| January 1960 | Severn tunnel Junction |
Whilst at Llanelly it spent about six months in store. After a service life covering 726,770 miles, it was withdrawn in July 1963 and sent to Woodham’s scrapyard in Barry. Rescued in November 1983, it came to Buckfastleigh where, after a lengthy overhaul, it returned to steam in 2005. Having cost less than £5000 to build, its restoration cost in excess of £350,000. The restoration was achieved with the aid of parts, including a boiler, donated by 2873.
In 2011 offers for the sale of the locomotive were invited but it remains under the ownership of the South Devon Railway.
3803 was on hire from the South Devon Railway to the Battlefield Line Railway for the seasons of 2011-2014.
It was taken out of service in 2015.
In February 3803 and the remains of the 2873 were sold by the South Devon Railway to the Dartmouth Steam Railway.
| Home Base | Current Status | Owner |
| Dartmouth Steam Railway | Awaiting overhaul | Dartmouth Steam Railway |
Preserved British Steam Locomotives 