AS BEARING true and costly witness is so central to the Christian calling, I was pleased to impute theological and faith-based resonance to D-Day: Secrets of the frontline heroes (Channel 4, Saturday). This was not another documentary reconstruction, or a programme of reminiscences of the few remaining veterans, but an account of the cameramen and film crews commissioned to record the events.

That years of meticulous planning preceded the invasion (surely the most complex military operation ever) is well known. New to me was the thoroughgoing commitment to documenting the Allies’ war as it returned to mainland Europe. As it was an American production, all focus was on participants from the United States: photojournalists and cameramen, but also Hollywood’s finest, from John Ford down, all showed their commitment to the war effort by volunteering to be embedded in the very first assault, lurching in the packed landing craft, jumping into the sea, running up the beaches armed only with unwieldy cameras, and reloading film under lethal fire.

The fear, injury, and death that they depicted was all around them; and the famous images and sequences gain in stature the more we appreciate the uncertainty of the outcome. The film had to be rushed back to England to be developed and processed so that newspapers could publish as soon as possible. Astonishingly, a film was edited within two days — as much as anything to be sent to Stalin, to prove to him that the Second Front that he had demanded from his allies had finally opened. The costly documentation had an immediate political as well as public urgency.

The three-part series Secrets and Spies: A nuclear game (BBC2, final episode Wednesday of last week) chronicled how utterly that alliance had, by the 1980s, degenerated into mutual threats of world annihilation. But, as Gorbachev assumed what had been Stalin’s throne, Reagan prepared to change his implacable anti-Soviet attitude: could at least some reduction of the nuclear stockpiles be negotiated?

What these documentaries revealed was the parallel and independent worlds of politics and espionage. Surely, spies ought to be the handmaids of their governments, providing them with clandestine information, subservient to whatever strategy is adopted. But we learned of the loyalties and determinations of the various Secret Services, and their own agendas to nurture their own agents and unmask their rivals’ — or, better still, turn them, so that they became double agents secretly working to undermine the Power that they ostensibly served.

Is the freedom and stability achieved and maintained at such appalling human cost through world war and cold war appropriately celebrated by, for example, Hidden Treasures of the National Trust (BBC2, Fridays)? Perhaps current political and social realities are so unbearable that, occasionally, we might award ourselves a respite, retreating into the Country House fantasy of glorious architecture, gardens, and art.