Sir Leslie Patrick Abercrombie FRIBA (/ˈæbərkrʌmbi, -krɒmbi/ AB-ər-krum-bee, -⁠krom-bee;[1] 6 June 1879 – 23 March 1957) was an English architect, urban designer and town planner.

He came to prominence in the 1940s for his urban plans of the cities of Plymouth, Hull, Bath, Bournemouth, Hong Kong, Addis Ababa, Cyprus, Edinburgh, Clyde Valley and Greater London.

In 1915 year was appointed as Lever Professor of Civic Design at Liverpool, soon becoming a nationally-known authority on town planning and the garden city movement.

He was later appointed as Professor of Town Planning at University College London, and gradually asserted his dominance as an architect of international renown, which came about through the replanning of Plymouth,[7] Hull, Bath, Edinburgh and Bournemouth, among others.

Of his post-war replanning of Plymouth, Sir Simon Jenkins has written: Throughout his life, he devoted his time to civic bodies.

From the Abercrombie Plan came the New Towns movement[14] which included the building of Harlow and Crawley and the largest 'out-county' estate, Harold Hill in north-east London.

He produced the Clyde Valley Regional Plan in 1946 with Robert Matthew that proposed the new towns of East Kilbride and Cumbernauld.

[15] In 1949 he published with Richard Nickson a plan for the redevelopment of Warwick, which proposed demolition of almost all the town's Victorian housing stock and construction of a large inner ring road.

[16] During the postwar years, Abercrombie was commissioned by the British government to redesign Hong Kong, for which he submitted plans in 1947.