In Aerospace Publishing and another v Thames Water Utilities Ltd. it was held that in order to claim wasted staff costs as damages for breach of contract the following principles apply; (1) the fact and the extent of the diversion of staff time have to be properly established – all relevant evidence needs to be put forward. It is important to maintain records to show how staff have spent their time (2) the claimant must establish that the diversion caused “significant disruption” to the business; (3) ordinarily it is reasonable for the court to infer that if there had been no disruption the staff involved would have generated revenue for the claimant in an amount at least equal to the cost of employing them during that time.

Bridge UK.Com Ltd v Abbey Pynford Plc. Evidence to support a claim for lost management time can be in the form of a witness statement from memory – it does not have to be from formal time records. However, the court may apply a discount to reflect the uncertainty of this method of calculation (in this case it was 20%).