Williams was a case heard in the UK Court of Appeal in 1983 and established that a mistake of fact can be a successful defence regardless of whether the belief is reasonable or not.

Facts

The defendant saw a young boy being dragged along the street by the victim while the youth shouted for help. The defendant intervened, believing that the young boy was being assaulted. It later came to light that the victim was in fact a policeman arresting the youth for mugging an old lady. At the trial the jury were told that mistake can only be a defence if the mistake was reasonable. The jury found a verdict of guilty.

At the appeal court the conviction was quashed.

Judgment

Lord Lane gave the leading judgement and stated that:

See also

• Beckford v R [1987] 3 All ER 425 Privy Council
• DPP v Morgan
  DPP v Morgan
  DPP v Morgan was a court case in the United Kingdom. It is frequently cited in matters of mistaken belief and mens rea of rape.-Case history:...
  
   [1975] 2 All ER 411
• B v DPP [2000] 1 All ER 823
• O'Grady 1987 3 All ER 420

External links

BAILII: Official transcript