The London and Birmingham Railway (L&BR) was an early railway company from 1833 until 1846, at which date it became a constituent part of the London and North Western Railway. The 112 mile (180km) long railway line that the company built between London and Birmingham was, when it opened in 1838, one of the first intercity railway lines in the world, and the first railway line to be built into London. It survives to the present day as the southern section of the West Coast Main Line.

The line was engineered by Robert Stephenson. It started at Euston Station in London, and travelled north-north-westward until reaching Rugby, where it turned west to Coventry and thence to Birmingham, In Birmingham the line terminated at Curzon Street Station, which it shared with the Grand Junction Railway (GJR), whose platforms were adjacent. This provided a link to the Liverpool & Manchester Railway (L&MR).

The construction of the London & Birmingham Railway was delayed by the works on the Kilsby Tunnel. As an interim measure the line was opened from London to Denbigh Hall near Bletchley 9 April 1836. The site was probably chosen as it was where the railway crossed Watling Street, then the Holyhead Road. Immense crowds of people assembled along the newly opened portion of the line to see the first train pass. The line between Birmingham and Rugby on the other side of the tunnel was opened on the same day. The railway company therefore arranged with Messrs Horne and Chaplin, coach proprietors, to convey passengers by road over the intervening 36 or 37 miles between Bletchley and Rugby. The line was completed throughout 17 September 1838.