Piercing the corporate veil describes the exceptional judicial step of disregarding a company’s separate legal personality to treat the acts or liabilities of the company as those of its controllers (typically shareholders or directors). It is not a statutory term in UK or Irish company law, but a case law‑based, descriptive expression used across multiple contexts, most often in insolvency, enforcement and fraud litigation.In England and Wales and Northern Ireland, following cases such as *Prest v Petrodel Resources Ltd*, courts will only pierce the veil in very narrow circumstances, usually where a company is used as a façade or sham to evade existing legal obligations or to perpetrate fraud. Similar principles apply in Scotland and Ireland, where courts also stress that incorporation and limited liability will be upheld unless there is abuse of the corporate structure.Piercing the corporate veil is distinct from other routes to personal liability (for example, wrongful trading, misfeasance, guarantees or statutory director liability). For practitioners, it is typically argued as a last resort, with a high evidential threshold and significant uncertainty as to outcome.