Variations arise under almost all construction contracts – terrestrial, marine and offshore. Alteration during the course of the work of the previously described and contractually agreed is common. Yet, as the authors of this new work correctly state: ‘Variation, as a subject, has been largely ignored.’

In the standard general works, the treatment is brief and largely focused on the valuation aspects involved and the effect upon the pricing of the works. The omission is curious. Important though that monetary aspect is, the very nature of a variation is that it gives rise to an issue as to what is and is not already within the scope of works. The need for a comprehensive and analytical treatment of variations has therefore long been felt.

That gap has now been filled by a work of real practical utility erected on rigorous intellectual underpinnings. The authors have approached the subject from first principles and rationalised a complex and diffuse topic. Starting from the issue of ‘scope’, which itself gives rise to many disputed questions, the authors then analyse the contractor’s obligations in respect of the works.

The circumstances in which variation arises under contractual rights to vary scope, under aspects within the contractor’s risk (such as defects) and under circumstances due to one or other of the parties, are then considered. The procedure for variations is dealt with in detail and, unusually, a chapter devoted to changes where there has been no variation instruction as such is included.

The consequences of variation both in valuation and, importantly, time/delay are then addressed.

The book is replete with judicious reference to authority. The analysis is anchored in the forms in everyday use and, throughout, the practical experience of the authors informs the text. The authors are to be congratulated on a clear and well-written book which will become an indispensable classic.

Authors: Michael Sergeant and Max Wieliczko
Publisher: Informa Law from Routledge, £295

Simon Rainey QC is a barrister at Quadrant Chambers