In Autumn 1962 The National Coal Board asked Frank Hampson to draw a series of cartoon strips to help them sell solid fuel. The strips were to feature The Chalmers family (the NCB suggested the name), decent working people with average incomes and the savvy to make themselves likeable. The hope was, that as readers got to know this fictional family, they'd recognise traits they could see in their own.
The NCB added a twist: Pop Chalmers was to be a coal miner. Like all his caste he was head of the household, loyal to his class, and proud the work miners did brought benefits to almost everyone. His youngest son Fred was also an NCB staffer, in their Customer Advisory Service.
The Chalmers' main job was to sell coal, but the NCB hoped for a side-benefit. Say a real coal miner happened on the campaign, and say he liked the way miners were depicted, might he not feel that, despite all, the bosses valued men like him? The Chalmers' second job was to give a fillip to staff morale.
The NCB asked Hampson for 25 strips, the first of which he delivered in early March 1963. On 6th June four million copies of this ad. rolled off the Daily Mirror presses. They went mostly into family homes, so were read by more than one person - six million Brits met The Chalmers that day. Scotland's campaign began three days later in the Daily Record. As well as these two papers, ads ran in the Daily Herald and Sunday Citizen. The last ad in Scotland ran on 5th January 1964.
Twenty-five strips was payday for Hampson, although it meant each strip ran just once in each paper, (usually one ad runs many times). This, plus NCB's ad-agent having no record of the campaign, means it's unlikely an ad-agency was involved.
N.B. The frames for each strip were originally presented in a single row but they have been split onto two rows each for web publication.