Criminal Damage Act 1991
“Without lawful excuse”.
6.— (1) This section applies to—
( b) any offence under section 3 other than one involving a threat by the person charged to damage property in a way which he knows is likely to endanger the life of another, and
( c) any offence under section 4 other than one involving an intent by the person charged to use, or cause or permit the use of, something in his custody or under his control to damage property in such a way as aforesaid.
(2) A person charged with an offence to which this section applies shall, whether or not he would be treated for the purposes of this Act as having a lawful excuse apart from this subsection, be treated for those purposes as having a lawful excuse—
( a) if at the time of the act or acts alleged to constitute the offence he believed that the person or persons whom he believed to be entitled to consent to or authorise the damage to (or, in the case of an offence under section 5 , the accessing of) the property in question had consented, or would have consented to or authorised it if he or they had known of the damage or the accessing and its circumstances,
( b) F7 [ … ]
F8 [ ( c ) if he damaged or threatened to damage the property in question or, in the case of an offence under section 4 , intended to use or cause or permit the use of something to damage it, in order to protect himself or another or property belonging to himself or another or a right or interest in property which was or which he believed to be vested in himself or another and the act or acts alleged to constitute the offence were reasonable in the circumstances as he believed them to be. ]
(3) For the purposes of this section it is immaterial whether a belief is justified or not if it is honestly held.
(4) For the purposes of subsection (2) a right or interest in property includes any right or privilege in or over land, whether created by grant, licence or otherwise.
(5) This section shall not be construed as casting doubt on any defence recognised by law as a defence to criminal charges.