It is important to remember that smacking should be a last resort. More information and advice on other ways of disciplining children is available from experts and charities who work with children, such as the NSPCC and Parentline Plus.
Advice about smacking from the NSPCC - "Encouraging better behaviour"
Parents have the right to make choices about reasonable punishments, but there is a fine line between "reasonable chastisement" (which is a defence in law) and assault (which is a criminal offence).
A smack might be considered to be reasonable chastisement if it is
Depending on the circumstances, an open-handed smack on a child's bottom, if it does not leave a mark, might therefore be considered "reasonable chastisement", whereas a smack on the head - even open-handed - might be considered assault, as it could cause harm.
It is against the law for teachers, nursery workers and childcare workers to smack another person's child. But anybody employed privately by a parent, such as a babysitter or nanny, may smack a child as long as the parent gives permission.