This paper describes the design and construction of the vast piled basement structures for the three terminal buildings at London Heathrow's £4·3 billion Terminal 5 project, together with 1 million m2 of associated aircraft pavements. The basements are up to 20 m deep and involved the excavation and reuse of 6·5 million m3 of gravel and clay. The aircraft pavement involved a number of innovations including development of a new high-strength concrete, which delivered a thinner construction and resulted in programme and environmental benefits.