Battery torts under Commonwealth precedent are subjected to a four point test to determine liability:[25]

Directness. Is the sequence of events connecting initial conduct and the harmful contact an unbroken series?
Intentional Act. Was the harmful contact the conscious object of the defendant? Did the defendant intend to cause the resulting harm? Though the necessity of intent remains an integral part of Commonwealth battery,[26] some Commonwealth jurisdictions have moved toward the American jurisprudence of "substantial certainty".[27] If a reasonable person in the defendant's position would apprehend the substantial certainty of the consequences of his actions, whether the defendant intended to inflict the injuries is immaterial.[27]
Bodily Contact. Was there active (as opposed to passive) contact between the bodies of the plaintiff and the defendant?
Consent. Did the plaintiff consent to the harmful contact? The onus is on the defendant to establish sufficient and effective consent.

http://en.wikipedia.org/wiki/Trespass#Battery