Geraldine Fleming of Knowles says As there is a contract between the parties, this is a clear breach of contract situation. Subcontractors and main contractors need to realise that the subcontractor is both obliged and entitled to complete the contractual scope of work, and by deleting the lightning protection work from the subcontractor's scope, and giving it to another subcontractor, this is a breach of contract by the main contractor. Such a breach would entitle the subcontractor to claim loss of profit - and the subcontractor needs to ensure that he produces the evidence to the main contractor to show what his loss of profit actually is. The subcontractor should write to the main contractor, pointing out the main contractor's breach, detailing what it would have cost him to do the work including labour and materials and providing a copy of the aluminium price and comparing it to the contract rate. The subcontractor then should be paid this loss of profit. Watch out for main contractor's including clauses in their terms and conditions that allow them to deduct work, and expressly state that a subcontractor would not be entitled to claim loss of profit. For further reading - have a look at the cases of Amec Building Limited v Cadmus Investments Co Limited (1996) and Abbey Developments Ltd v PP Brickwork Limited (2003).