The Leamington–Rugby line was a railway running from Leamington Spa to Rugby. It was a 15-mile branch line built by the London & North Western Railway (LNWR) and opened in 1851. The branch connected Leamington with the mainline from London to Birmingham (now the West Coast Main Line which had been opened in 1838 by the LNWR's predecessor, the London & Birmingham Railway (L&BR).
The original proposal for the line was put forward by the Rugby, Leamington and Warwick Railway Company (which soon became the Rugby and Leamington Railway). The Act for the railway received Royal Assent on 13 August 1846. The undertaking was sold to the LNWR on 17 November 1846.
However, the line from Rugby was not the first to reach Leamington. The L&BR had opened a branch from its mainline at Coventry in 1844 which terminated at Milverton, midway between Leamington and Warwick. This terminal station was originally called Leamington despite being a mile from the town. When the LNWR line from Rugby was built in 1851, it extended west of Leamington crossing the River Leam on a stone viaduct to make an end-on connection to the branch from Coventry.
Meanwhile, however, the Great Western Railway (GWR) Oxford to Birmingham line was being constructed through Leamington and the line from Rugby ran parallel to it. The GWR's original Leamington station opened in 1852 and its successor on the same site is still open today. Two years later, the LNWR opened its own station alongside the GWR station. The LNWR's station was north of the GWR's and at a slightly lower level. This new station was named Leamington Avenue and the former LNWR terminus on the line from Coventry was renamed Warwick (Milverton).