This chapter examines of the role of the lex fori in English private international law before proceeding to examine the rules of the conflict of laws applicable in an English court. Issues for which the rules of the conflict of laws select the lex fori as the law to be applied include grounds for the dissolution (as distinct from nullity) of marriage, even if the marriage has little or nothing to do with the United Kingdom; or settlement of the distribution of assets in an insolvency even though there may be significant overseas elements. Where the rules of the conflict of laws select a foreign law, its application, even though it is proved to the satisfaction of the court, may be disrupted or derailed by a provision of the lex fori instead. The remainder of the chapter covers procedural issues; penal, revenue, and public laws; and public policy.