Speaking at last week’s Labour Party conference, Unite assistant general secretary Tony Burke said: “It is time employers found guilty of killing or seriously maiming their staff go to prison.”

He said: “We want to see a secondary duty on directors and senior managers in the corporate manslaughter law, which means if they are directly responsible for corporate manslaughter they too can be held liable and, if necessary, put behind bars.”

Unite, which is the UK’s largest trade union, welcomed legislation introduced this year that will provide greater physical protection for people at work, but said that it did not go far enough.