There is a close similarity to contributory negligence and the distinction is even harder to differentiate following the 1945 statute “The Law Reform (Contributory Negligence) Act 1945”
As a result of the introduction of this piece of legislation the courts have become increasing less willing to make a finding of volenti preferring to apportion loss between the parties
So it’s no longer a practical defence but could be claimed as a defence in the hope of avoiding having the full amount of damages awarded against you