David McKie is an agent with the DIC.
That rather unfortunately named acronym is for an very obscure member of the British intelligence community, the Department For Internal Concerns. In a prologue for the first recorded adventure, we are told "Winston Churchill ... created an espionage network across the United Kingdom in 1940 to assist the resistance fighters and to watch the government, the law enforcement agencies, the army, the navy, the air force, the people of the towns and cities and generally speaking the streets, the transport routes and coastline for any attempts to infiltrate the land, the communities and the forces organised to protect the country. This agency was made up of ordinary citizens, chosen for their loyalty, their levels of intelligence and their foresight."
"The police, Special Branch, MI5 and MI6 watch for threats against the UK, domestic and foreign. They have done since Churchill's time and before, but since 1940 those watchmen and watchwomen of the known and recognised services have been in turn watched by Churchill's war time secret network. It's a little known fact that the network of watchers set up by Churchill in 1940 still exists to this day and there is still a web of men and women in every town and village across the UK working for a branch of the civil service known as the Department for Internal Concerns or the DIC. They are the unseen and unknown; they are those who watch the watchers."
The agent that we follow most closely, McKie, is a tall, broad-shouldered Scot with sandy hair. Prior to getting accepted by the DIC, he had worked as a civil servant in the Customs Department. After graduating from college with a degree in history, he first worked in the Scottish office but had not taken to the desk work. A transfer to Customs got him transferred to Dover and an opportunity to get out of the office, at least as far as his wife Mary could see, but it seemed "the adventurer in him had stopped him getting further up the promotion 'ladder'" which concerned her. She was pleased to learn about the transfer to the London office.
She had been surprised by the month-long training course he had to attend up north; not knowing her husband's new real line of work, she did not know that he had excelled there in every course they taught, including being especially good in unarmed combat and in firearms. For that reason she did not know that McKie would be assured that it was "rare, sometimes unheard of for an operative of DIC" to use either; this is fortunate because it would seem McKie would indeed use both far more often than he was told.