“2.25. 1. any of the events which are stated to be a cause of delay is a Relevant Event; and 2. completion of the Works or of any Section has been or is likely to be delayed thereby beyond the relevant Completion Date, 3. and provided that (a) the Contractor has made reasonable and proper efforts to mitigate such delay; and (b) any delay caused by a Relevant Event which is concurrent with another delay for which the Contractor is responsible shall not be taken into account then, save where these Conditions expressly provide otherwise, the Employer shall give an extension of time by fixing such later date as the Completion Date for the Works or Section as he then estimates to be fair and reasonable.”
“The third proposition must be treated with care. It seems to me that, insofar as an extension of time clause is ambiguous, the court should lean in favour of a construction which permits the contractor to recover appropriate extensions of time in respect of events causing delay. This approach also accords with the principle of construction set out by Lewison in The Interpretation of contracts (3rd edition 2004). That principle reads as follows: ‘Where two constructions of an instrument are equally plausible, upon one of which the instrument is valid and upon the other of which it is invalid, the court should lean towards that construction which validates the instrument.’ ”
“it is not a question of the Contract being unworkable but, rather, a consequence that, applying Multiplex and in particular by the application by the first and second propositions referred to above, time is at large.”
“any impediment, prevention or default, whether by act or omission…..”
"The conduct therefore has to render it "impossible or impracticable for the other party to do the work within the stipulated time"
“I hold that in relation to both its extension of time claim and its claim in reliance on the prevention principle it [ie Adyard] has to establish causation in fact, which means showing that the variations were likely to or (as the case may be) did cause actual delay to the progress of the works.”
“Hamblen J's analysis indicated that, if there were two concurrent causes of delay, one which was the contractor's responsibility, and one which was said to trigger the prevention principle, the principle would not in fact be triggered because the contractor could not show that the employer's conduct made it impossible for him to complete within the stipulated time. The existence of a delay for which the contractor is responsible, covering the same period of delay which was caused by an act of prevention, would mean that the employer had not prevented actual completion. Throughout his analysis, Hamblen J stressed the importance of the contractor proving delay to the actual progress of the work as a result of the alleged act of prevention.”
“Accordingly, I conclude that, for the prevention principle to apply, the contractor must be able to demonstrate that the employer's acts or omissions have prevented the contractor from achieving an earlier completion date and that, if that earlier completion date would not have been achieved anyway, because of concurrent delays caused by the contractor's own default, the prevention principle will not apply.”