this railway branch was completed as a double-track line in 1885. it was built by the london and south western railway in response to the planned didcot, newbury and southampton railway. the dn&sr, with the support of the l&swr's rival the great western railway, planned to build a main line route from the midlands to southampton in the heart of the l&swr's territory, with its own terminus and an entirely separate line. the l&swr was well aware that the dn&sr, like most start-up railway companies, was short of finances. it built 7.5-mile (12 km) fullerton to hurstbourne line to provide a complete line between hurstbourne and romsey. the l&swr would offer the dn&sr the much cheaper alternative of building its line from newbury to hurstbourne, where its trains would then run on the new route along l&swr track to the southampton terminus. the dn&sr would get its route to southampton whilst the l&swr would be able to exercise control over its competitor.