325Evidential burden as respects excuses
(1)This section applies to an offence under any of sections 1 to 41, 107, 229, 266 and 306 which is such that a person who would otherwise commit the offence—
(a)does not do so if he has a lawful excuse; or
(b)does not do so if he has a reasonable excuse.
(2)In proceedings for an offence to which this section applies, the defendant is to be treated as not having had a lawful excuse or reasonable excuse (as the case may be) unless sufficient evidence is adduced to raise an issue as to whether he had such an excuse.