Construction of Westminster Station, London

The most complex and technically demanding station on the Jubilee Line Extension Project, with the deepest basement in London, was constructed within the political heart of the country and under one of London's oldest underground railway stations. Various civil engineering techniques such as tunnelling, piling, diaphragm walling and top-down construction were used to construct the station escalator hall and foundations to a prestigious new parliamentary building. Buildings surrounding the work-site, together with the District and Circle Line station passing diagonally through it, severely restricted construction access and working space. Major challenges to the construction team included movement control of adjacent structures such as St Stephen's Clock Tower (Big Ben) and a major trunk sewer, and rebuilding the existing station while maintaining an uninterrupted flow of passengers and trains through the station. This paper describes the construction of the new Westminster Station (excluding tunnel works), which was part of Contract 102 of the Jubilee Line Extension Project: Green Park to Waterloo Tunnels, Westminster and Waterloo Stations.