In Petrodel Resources Ltd v Prest [2013], Lord Sumption stated that there is only one instance in which the courts can pierce the veil. What is this one instance? Where a person is under an existing legal obligation which he deliberately evades or whose enforcement he frustrates by interposing a company under his control. Where a parent owes the employees of its subsidiary a duty of care. Where a group of companies are to be regarded as a 'single economic unit. Where a subsidiary is acting as an agent for the parent