The Berks and Hants Railway comprised two railway lines built simultaneously by the Great Western Railway (GWR) south and west from Reading in an attempt to keep the London and South Western Railway (LSWR) out of the area that it considered to be its territory in England.
One line ran from Reading to Hungerford and was entirely in the county of Berkshire ("Berks"). A later Berks and Hants Extension Railway continued the Hungerford line to Devizes in Wiltshire. Since 1906 part of this route has formed the direct Reading to Taunton Line used by trains to Devon and Cornwall. The term 'Berks and Hants Line' has been used intermittently by officials and passengers for the whole route from Reading to Taunton even though it does not enter Hampshire and most was never built by the Berks and Hants Railway.
The second line ran from Reading to Basingstoke and terminated adjacent to the LSWR station there. Later the GWR station was closed and trains on the Reading to Basingstoke Line now use a platform of the rebuilt LSWR station.
In 1844, the GWR proposed a 7 ft (2,134 mm) broad gauge branch line from Pangbourne railway station to Newbury while the LSWR was promoting an alternative 4 ft 8 1⁄2 in (1,435 mm) standard gauge branch from Basingstoke to Newbury and Swindon, the heart of GWR territory. However, the following year saw an Act of Parliament passed to allow the construction of the GWR-backed Berks and Hants Railway from Reading to both Basingstoke and Hungerford. The capital for this company was put forward in the names of GWR directors, and the following year a new Act of Parliament saw the Berks and Hants formally absorbed into the larger company.