Silvertown Tunnel, London - Banagher Precast Concrete
The Silvertown Tunnel is set to be the largest diameter tunnel ever undertaken in the UK. Stretching beneath the River Thames to connect Silvertown and the Greenwich Peninsula, the £1 billion project aims to ease congestion through the Blackwall Tunnel while improving public transport links across East London. Opening in 2025, it also reflects a wider shift toward more sustainable and efficient infrastructure delivery, much of which has been made possible through the use of precast concrete.
Precast was chosen for its quality, reliability and ability to reduce environmental impact. Supplied by Banagher Precast Concrete, more than 10,000 tunnel segments were manufactured offsite and transported to site for installation. Factory production offered significant advantages, including rigorous quality control, consistent strength and minimal disruption on site.
Working closely with the Riverlinx JV (Ferrovial, BAM Nuttall and SK Ecoplant) and consulting engineers, Banagher delivered a UK first with the development of intricate cross-passage segments that removed the need for temporary propping. This bespoke engineering solution enabled a faster and safer build, showcasing the flexibility and adaptability of precast in complex underground works.
Sustainability was embedded throughout the project. The concrete mix included 39% ground granulated blast furnace slag (GGBS), a lower-carbon cement alternative and the use of steel-fibre reinforcement further reduced reliance on traditional steel bar. Together, these innovations saved approximately 1,480 tonnes of CO₂. As part of its wider commitments, Banagher also planted 1,000 trees and maintained its ISO 17025 accreditation for materials testing.
The Silvertown Tunnel project not only highlights the many advantages of precast concrete, precision, performance and carbon savings but also points to an increasingly circular and low-carbon future for infrastructure in the UK.