What are the penalties for non-compliance with an Improvement or Prohibition Notice?

Under the Health and Safety at Work etc Act 1974 it is a very serious offence to contravene any requirement or prohibition imposed by an Improvement or Prohibition Notice issued by a health and safety inspector from an enforcing authority. Doing so can result in 12 months' imprisonment and/or an unlimited fine in the lower courts, while the maximum sentence in the higher courts is two years' imprisonment and/or an unlimited fine.