The British Rail Class 141 was the first production model of the Pacer diesel multiple unit (DMU) railbus.

During the 1980s, British Rail (BR) was interested in replacing its first generation diesel multiple units, particularly in the use of railbuses to service its lightly used branch lines. It was decided to develop such a vehicle with a high level of commonality with the widely used Leyland National bus, leading to its modular design serving as the basis for the design.

Several single and two-car prototypes were constructed and evaluated, before an order was placed with British Leyland for twenty two-car Class 141 units during 1984. During their operating lives, the units were tasked with various passenger services across the UK for 13 years. Following withdrawal, a large portion of the units were exported to Iran where they operated for a further eight years, giving the Class 141 a total lifespan of 21 years.

Following the end of their career with British Rail, 12 Class 141s were sold to Islamic Republic of Iran Railways and were exported during 2001/2002. All units have since been withdrawn and replaced by new DMUs. Two units (106 & 112) were exported to the Netherlands, but these were both scrapped during 2005. Only a handful of units have remained in the United Kingdom, of which two units are in preservation: 141108 at the Colne Valley Railway, and 141113 at the Midland Railway – Butterley. Two units (141103 and 141110) were formerly preserved at the Weardale Railway, of which 141103 and the one remaining car from 141110 were scrapped in March 2018.