Under the English common law rule known as the 'forfeiture rule', a person who has unlawfully killed another is barred from acquiring any benefit as a consequence of the killing, and all inheritance and other rights are normally forfeit. The Forfeiture Act 1982 (c. 34) is an Act of Parliament of the United Kingdom which allows the court to relax or to set aside operation of the rigid common law rule where "the justice of the case" so requires (other than to benefit a murderer).

Under section 1(1) the 'forfeiture rule' is defined as "the rule of public policy which in certain circumstances precludes a person who has unlawfully killed another from acquiring a benefit in consequence of the killing". Section 2 provides:

• (1) The court shall not make an order under this section modifying the effect of the forfeiture rule in any case unless it is satisfied that, having regard to the conduct of the offender and of the deceased and to such other circumstances as appear to the court to be material, the justice of the case requires the effect of the rule to be so modified in that case.
• (2) Where a court determines that the forfeiture rule has precluded a person (in this section referred to as "the offender") who has unlawfully killed another from acquiring any interest in property ... the court may make an order under this section modifying the effect of that rule.

Section 5 prevents the court from relaxing or setting aside the normal forfeiture rule to benefit a person who has been convicted of murder.

• Estates of Deceased Persons (Forfeiture Rule and Law of Succession) Act 2011
• Slayer rule - similar rule in United States law