Listed in order of appearance: Many characters were portrayed by recurring actors throughout the series' run.
Probably the most prolific recurring actor was Denzil Howson, who appeared regularly in minor parts throughout the entire series' run.
He played everything from a Salvation Army Major, to Doctors, Judges, Lawyers, fathers and husbands of prisoners and the head of the Social Welfare department.
There were many other actors who played multiple minor roles too such as Will Deumer (including roles as Lionel Fellowes, a Doctor, Sailor, Boss) and Arthur Barradell-Smith to name but two.