The SER was granted permission to build a line from Ashford in Kent to St Leonards, East Sussex in 1845. The LBSC reached St Leonards from the following year. This gave the LBSC a shorter route to than the SERs route, then still under construction. The SER sought permission to extend their branch from Tunbridge Wells across the High Weald to reach Hastings. Authorisation for the construction of a line to Hastings was obtained on 18June 1846, Parliament deemed the line between Ashford and St Leonards to be of military strategic importance. Therefore, they stipulated that this line was to be completed before any extension was built from Tunbridge Wells. The extension into Tunbridge Wells opened on 25November 1846 without any public ceremony. In 1847, the SER unsuccessfully challenged the condition that the line between Ashford and St Leonards be completed first. That line was opened in 1851, passing through Hastings and making an end-on junction with the LBSC line from Lewes.