What does mens rea mean?

Mens rea is the latin phrase for "guilty mind", which when applied to law scenarios is most simply explained as the defendant (the person committing the crime) intended or planned to commit the crime. For a general offence, the defendant can't be convicted if he doesn't have some form of mens rea.

There are different types of mens rea: intention (both direct and indirect) as well as recklessness. Direct intention was shown in the case of Mohan as aiming to bring about the prohibited consequence, so in other words choosing to commit the crime. Indirect intention was shown in the case of Woolin, which questions whether the consequence was a virtual certainty, and if the defendant realised this. Recklessness is defined in Cunningham as the defendant realises a risk and takes the action anyway, so they don't actually have to want the consequence but just realise it could happen.