The country is groaning under the weight of commemorations, exhibitions, publications and programmes all marking significant anniversaries of World War One, but the underlying message – lest we forget – remains as potent as ever, perhaps even more so in these tumultuous times.

The world now knows him as Lord Crawley, stiff-backed in white tie and tails, regimental garb or, for relaxation, tweed. But before he became the face of Downton Abbey – and of bumbling institutional incompetence in Twenty Twelve and W1A – Hugh Bonneville could be seen in roles of considerable depth and range, including a moving Philip Larkin and a brutish husband in the BBC's Daniel Deronda.

There came a moment, around three years ago, when MyAnna Buring suddenly seemed to be in everything. "I'm so sorry!" she shrieks (ironically) when I point this out to her. She had given warning of her arrival by appearing in Ben Wheatley's Kill List and, rather more prominently, as Tanya (who as you'll know was a vegetarian vampire from the Denali coven) in the concluding pair of Twilight films.

Going into this programme, it dawned on me that I knew next to nothing about Mark Rylance's background – where he came from, who his parents were, what he does in his personal life. Having reached the end credits I was little the wiser, other than having learned that he has a wife called Claire, since none of it fell within the purview of Melvyn Bragg's interviewing.

I hope someone by now has told Neil Patrick Harris how to pronounce David Oyelowo’s surname, but if anyone wants to see how not to host an Oscars, Harris’s stewardship of the 87th annual Academy Awards can provide that service in spades.

There was a brief moment back in the day when Sylvester Stallone thought he ought to be a serious actor (remember Cop Land?), but posterity will surely recall him as the King of the Franchise. As if Rocky and Rambo weren't enough, the 68-year-old Stallone is now enjoying a major string of paydays with The Expendables, and this third instalment will merely whet the global appetite for more.

Celia Imrie is admired and loved as a comic actress. Her conversation, just as much as her performances, is full of her trademarks: sudden darting looks, alertness, natural timing, changes of register. They will all be in display in her cabaret show Laughing Matters.

The late rise of Ruth Jones, who has been made an MBE, is a blessed relief. According to the prevailing rules of ageism and lookism, Jones should still be plugging away in supporting roles, typically as the large gobby sidekick which for years looked like the outer limit of her casting range.

Inevitably, an aura of fin-de-siècle gloom hung heavily over this final Poirot. So daunting was the prospect of terminating his 25-year career-defining stint as Belgium's finest (albeit imaginary) export that David Suchet insisted on shooting the last one before the others in the concluding series.

It has to be partial, because out of the 10 opera productions from the iconoclastic French actor-director, who died yesterday of lung cancer at the age of 68, I’ve seen but two, on screen only – but a big two at that – and only three of his 11 films. Yet they all had a tremendous impact, one way or another.