The relevant compensation event is clause 60.1 (19). The clause actually says “stops the Contractor completing the works by the date shown on the Accepted Programme”. “Stops” is a strong test and means that it is not just difficult or more expensive to complete the works. The event also has to be one which:
neither Party could prevent,
an experienced Contractor would have judged at the Contract Date to have such a small chance of occurring that it would have been unreasonable for him to have allowed for it and
is not one of the compensation events stated in the contract.