The Great Central Main Line (GCML), also known as the London Extension of the Manchester, Sheffield and Lincolnshire Railway (MS&LR), is a former railway line in the United Kingdom. The line was opened in 1899 and built by the Great Central Railway running from Sheffield in the North of England, southwards through Nottingham and Leicester to Marylebone in London.

The Manchester, Sheffield and Lincolnshire Railway (MS&LR) was formed in 1847 when the Sheffield, Ashton-under-Lyne and Manchester Railway joined with authorised but unbuilt railway companies, forming a proposed network from Manchester to Grimsby. It pursued a policy of expanding its area of influence, especially in reaching west to Liverpool, which it ultimately did through the medium of the Cheshire Lines Committee network in joint partnership with the Great Northern Railway and the Midland Railway.