Thames Drilling Yields Crucial Data for Westminster Palace Restoration
Between April and September 2025, extensive ground investigations were conducted along the River Terrace and the River Thames as part of the Restoration and Renewal of the Palace of Westminster. Fourteen boreholes were drilled into the Thames, reaching depths of up to 74.5 meters to map geological conditions. Additionally, two boreholes were made on the Parliament’s River Terrace.
Key Discoveries from Thames Drilling
Significant discoveries emerged from these investigations, including the remains of a 19th-century cofferdam designed by architect Charles Barry. This data will inform future designs, particularly regarding basement usage and service routes.
- 14 boreholes drilled in the River Thames
- 2 boreholes drilled on Parliament’s River Terrace
- Discovery of Charles Barry’s 19th-century cofferdam
Innovative Engineering and Logistics
This project marked the first instance of river access being utilized for equipment delivery to the Palace of Westminster, ensuring minimal disruption to the surrounding area. A jack-up barge was employed, allowing specialist teams to carry out essential drilling assessments.
Lord McFall, the Lord Speaker, expressed admiration for the experts involved, remarking on the historical significance of discovering ancient riverbed materials. Judith Cummins MP, Chair of the R&R Programme Board, highlighted the extensive planning underway to restore the Palace of Westminster.
Geological Insights and Monitoring Techniques
Andy Piper, the Design and Engineering Director, noted that these investigations provided invaluable insights into previously unmapped geological conditions east of Parliament. Essential data will play a key role in informing design decisions for future construction efforts.
On the River Terrace, boreholes aimed to confirm boundaries between major geological formations: the London Clay Formation and the deeper Lambeth Group. London Clay is notable for its stability in tunneling, while the Lambeth Group poses challenges with high water pressures.
Environmental and Heritage Considerations
Monitoring devices were installed on and near the River Terrace to track changes in water quality and conditions over time. Vibration monitoring devices were also deployed to evaluate any effects on the historic structure and its collections during construction.
James Palmer, Director of Marine Operations at the Port of London Authority, emphasized the potential of the Thames for safe and environmentally friendly construction logistics. Utilizing the river can alleviate congestion and reduce emissions while addressing complex engineering challenges.
Next Steps in the Restoration and Renewal Programme
This phase of investigations builds on previous borehole surveys across the Parliamentary Estate, enriching the data that supports advanced digital modelling for the Palace’s future. As laboratory testing continues, insights have already surfaced regarding the dismantling of Barry’s cofferdam, indicating a potential strategy of cutting down timber piles rather than complete removal.
Future proposals for the Palace’s Restoration and Renewal, including delivery options, timelines, and financial considerations, are expected to be released soon. This multibillion-pound investment aims to foster opportunities for craftsmen and specialists throughout the UK.
