In English law even the lightest touch can be a crime of battery
English law treats battery as an offence against personal autonomy, so no injury is needed. The slightest unwanted application of force can qualify. Only an assumed consent to the jostle of ordinary life, like brushing past strangers on a crowded train, keeps most commuters on the right side of the law.
Battery means intentionally making harmful or offensive physical contact with someone who has not agreed to it. American common law phrases it broadly as any unlawful or unwanted touching, whether by the aggressor directly or by something the aggressor sets in motion. Across jurisdictions two elements recur: the defendant causes the contact, and intends or knows that it will happen. Under the US Model Penal Code and in some places, recklessness is enough. Cases can be simple or aggravated, and battery can arise outside fights, for example when a doctor performs a procedure the patient never consented to.
In England and Wales battery exists at common law, with two familiar ingredients: an unlawful touch or use of force, and intention or recklessness about it. Worse injuries, classed as actual or grievous bodily harm, are instead governed by an Act of Parliament dating from 1861. Canada takes another route entirely, with no battery offence in its criminal code, only assault in its various grades.
Terminology trips people up. In daily speech an assault means a physical attack, but legally that attack is battery, while assault means making someone expect one. Because both can fall under the heading of common assault, charges are often worded as assault by beating, which simply means battery. Some argue that the offence called sexual assault would be more accurately named sexual battery.
Even battery's legal status is disputed. In DPP v Taylor and DPP v Little, judges decided that section 39 of a 1988 criminal justice statute had turned it into a creature of legislation, even though that section never defines it. In Haystead v DPP, another court suggested in passing that it remains a common law crime. Separately, the 2015 offence of controlling or coercive behaviour has produced sentencing guidance that can lengthen penalties for battery within abusive relationships.
Source: Battery (crime)