Henry Boot Construction Ltd v Alstom Combined Cycles
The case of ‘Henry Boot Construction Ltd. v Alstom Combined Cycles’ [1999] set a precedent that contractor’s rates do not become reasonable or unreasonable by the execution of variations.
The extent to which bill of quantities (BoQ) rates are applicable for valuing variations in the works, is a common cause of conflict on projects, particularly when there are substantial changes in quantities. This can be a particular issue if the rate in question is abnormally high or low due to the fact that an error has been incurred. Contractors argue that abnormally low rates compound losses, while clients point out that abnormally high rates exaggerate contractor profits.
In the case of Henry Boot Construction Ltd. v Alstom Combined Cycles, Henry Boot Construction Ltd. was employed by Alstom to undertake civil engineering works at a power station. Boot quoted a price for temporary sheet piling and this figure was included in the contract. As the works proceeded however, variation instructions affecting the sheet piling were issued.
Boot’s price was found to have been calculated incorrectly, meaning that the additional quantity required by the variation would have given them a large profit. Boot argued that the contract rates must be adhered to whereas Alstom argued that a fair valuation should be made.
At the trial, the judge emphasised the importance of the contract rates, ruling that they were ‘sacrosanct, immutable, and not subject to correction’ on the basis of one party’s dissatisfaction with them. He referred to Clause 55(2) in the relevant ICE Standard Form (6th ed.) contract which stipulated that there should be no rectification of errors, omissions or estimates, and that a mistake in a rate or price bound both parties equally.
The Court of Appeal endorsed the judge’s ruling in 2000, confirming that pricing errors do not allow the parties to adjust the rates.
The rates may however be adjusted where they are used to value variations:
- Where the works are not executed under similar conditions.
- Where the rate is rendered inapplicable by a substantial change in the quantities.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
The UK's Modern Industrial Strategy: A 10 year plan
Previous consultation criticism, current key elements and general support with some persisting reservations.
Building Safety Regulator reforms
New roles, new staff and a new fast track service pave the way for a single construction regulator.
Architectural Technologist CPDs and Communications
CIAT CPD… and how you can do it!
Cooling centres and cool spaces
Managing extreme heat in cities by directing the public to places for heat stress relief and water sources.
Winter gardens: A brief history and warm variations
Extending the season with glass in different forms and terms.
Restoring Great Yarmouth's Winter Gardens
Transforming one of the least sustainable constructions imaginable.
Construction Skills Mission Board launch sector drive
Newly formed government and industry collaboration set strategy for recruiting an additional 100,000 construction workers a year.
New Architects Code comes into effect in September 2025
ARB Architects Code of Conduct and Practice available with ongoing consultation regarding guidance.
Welsh Skills Body (Medr) launches ambitious plan
The new skills body brings together funding and regulation of tertiary education and research for the devolved nation.
Paul Gandy FCIOB announced as next CIOB President
Former Tilbury Douglas CEO takes helm.
UK Infrastructure: A 10 Year Strategy. In brief with reactions
With the National Infrastructure and Service Transformation Authority (NISTA).
Ebenezer Howard: inventor of the garden city. Book review.
The Grenfell Tower fire, eight years on
A time to pause and reflect as Dubai tower block fire reported just before anniversary.
Airtightness Topic Guide BSRIA TG 27/2025
Explaining the basics of airtightness, what it is, why it's important, when it's required and how it's carried out.
Construction contract awards hit lowest point of 2025
Plummeting for second consecutive month, intensifying concerns for housing and infrastructure goals.
Understanding Mental Health in the Built Environment 2025
Examining the state of mental health in construction, shedding light on levels of stress, anxiety and depression.
The benefits of engaging with insulation manufacturers
When considering ground floor constructions.
Lighting Industry endorses Blueprint for Electrification
The Lighting Industry Association fully supports the ECA Blueprint as a timely, urgent call to action.