Common law that mens rea was an essential element to a conviction unless parliament indicates the contrary
B V DPP
Offences not under strict liability must have some level of mens rea, if this is lacking no conviction can be upheld
Sweet V Parsely
Need for mens rea can be displaced where the statute is concerned with social policy, i.e public safety
Gammon Lt V A-G of Hong Kong
While it is presumed mens rea is necessary, in certain cases mental intention was not needed
PWR V DPP