When introduced in the House of Commons on 22nd June 2005 (by Alan Williams MP who came seventh in the private members' ballot) the purpose of what was then called the "Emergency Workers (Protection) Bill" was described as being "to make it an offence to assault or impede persons who provide emergency services; and for connected purposes". That remains a good overall description.

For relevant general notes go to Criminal law aspects/offences under employment legislation/harassment