Legal Dictionary

conclusive presumption

Legal Definition of conclusive presumption


See also

Definition of conclusive presumption


conclusive presumption (plural conclusive presumptions)

  1. (law) A matter that deemed by law to be true, and therefore provides no opportunity for evidence to the contrary to be presented.

Related terms

Further reading

A conclusive presumption (also known as an irrebuttable presumption) is a type of presumption used in several legal systems.

England and Wales

In English law, a conclusive presumption is a presumption of law that cannot be rebutted by evidence and must be taken to be the case whatever the evidence to the contrary.

For example, the doli incapax rule conclusively presumes that a child less than ten years old cannot be held legally responsible for their actions, and so cannot be convicted for committing a criminal offence. The age was seven at common law, and raised by the Children and Young Persons Act 1933 to eight (section 50) and by the Children and Young Persons Act 1963 to ten. A similar rebuttable presumption, that a child between the ages of ten and fourteen was not capable of committing a criminal offence, was abolished by the Crime and Disorder Act 1998. Now the age of criminal responsibility in England and Wales is 10.

Many conclusive presumptions have been abolished in recent years. For example:

  • the rule that conclusively presumed that a boy under the age of 14 years cannot have sexual intercourse, and so cannot therefore be convicted as a principal for the offences of rape, buggery or any other offence where the actus reus involves sexual intercourse (abolished by the Sexual Offences Act 1993)
  • the year and a day rule, which conclusively presumed that a death was not murder (or any other form of homicide) if it occurred more than a year and a day since the act (or omission) that was alleged to have been its cause (abolished by a Law Reform (Year and a Day Rule) Act 1996).
  • the rule that, by marriage, a wife was conclusively presumed to have given her irrevocable consent to sexual intercourse with her husband, so a husband could not rape his wife (the offence of rape was then defined in section 1 of the Sexual Offences Act 1956 as "unlawful" sexual intercourse without consent, and the word "unlawful" was taken to make a distinction from "lawful" sexual intercourse within marriage). This rule was overturned by the House of Lords in the case of R. v. R. in 1991, and its abolition made clear by the Criminal Justice and Public Order Act 1994, which deleted the word "unlawful" from the definition.

The new addition to the Crime and Disorder Act 1998 (c. 37) states

    Section 34: Abolition of rebuttable presumption that a child is doli incapax. The rebuttable presumption of criminal law that a child aged 10 or over is incapable of committing an offence is hereby abolished.

See also the case of R v JTB [2009] UKHL 20. Despite obiter comments in the earlier case of Crown Prosecution Service v P [2007] EWHC 946 (Admin) (27 April 2007), doli incapax as a defence and as a presumption for children aged 10 or above was abolished by section 34 Crime and Disorder Act 1998.

Tasmania (Australia)

In Tasmania, logging practices which are destroying habitat of threatened species were made legal after a clause was added to the Regional Forest Agreement which made the conclusive presumption that environmental management strategies and prescriptions were being applied. This prevented a legal case against the forestry industry being taken to a higher court.


  1. Wiktionary. Published under the Creative Commons Attribution/Share-Alike License.


1.     landed property
2.     common stock
3.     lex situs
4.     lex causae
5.     lex fori
6.     status quo
7.     buggery
8.     conclusive presumption
9.     interlocutory
10.     writ of seizure and sale