If it ain't broke don't fix it, and writer Heidi Thomas obviously has no intention of tinkering with the Call the Midwife formula. Virtually nothing has changed, except that there's a new character, Sister Winifred, while Chummy (Miranda Hart) is now living with her husband PC Noakes (Ben Caplan) and has a baby son. However, you can't keep a born midwife down, and Chummy's return to the Nonnatus House mothership by the end of the episode was a foregone conclusion.

“Her most devastating surprise ever.” Thus spake The Guardian, a quote happily slapped across the cover of the first paperback edition of Agatha Christie’s 1967 thriller Endless Night. While I wouldn’t go quite that far – that honour goes to her still startling, genre-busting The Murder of Roger Ackroyd (1926) – it’s a compelling little chiller. Small wonder that ITV wanted it for their franchise. Just one tiny problem: it’s a crime novel without a detective.

Mr Arkadin, wedged between two greats – Othello and Touch of Evil – is Welles’ most chaotic film, its production scarred by budget restraints and a terminal quarrel with the producer, who barred Welles from the final edit – yet again. What you see is often a mess of dismal dubbing, painfully abrupt (as well as daringly innovative) cuts, and swathes of voiceover to cram in the necessary plot explication.

Allen Ginsberg was once approached by two young acolytes eager to discuss literature. The bearded eminence of the Beats was the soul of generosity, giving up no small allowance of time to share his vast knowledge and experience. How they must have basked in the glow as a great poet treated them as equals. At a certain point, having put in sufficient effort, Ginsberg deemed it a good moment to change the subject. “So,” he said, “either of you guys suck cock?”

How do you solve a problem like...no, not Maria, Candide? Musicals are loved for their scores – and Leonard Bernstein’s one for this really is a cracker – but they’re held together by their books, i.e. the script/dramatic context that makes audiences care about the characters and plot. Filled to bursting with good intentions, Matthew White’s exuberantly rough’n’tumble new Menier production does its damnedest but there’s no disguising the fact that Lillian Hellman’s adaptation of Voltaire’s satire of inexhaustible optimism remains tension-free. 

How much time does anyone want to spend in the company of Kim Philby? BBC Four’s Storyville allotted him 75 minutes, which isn’t much to tell the story of a third man with two paymasters and four wives. And yet this portrait somehow contrived to outstay its welcome. This is not to come over all huffy Heffer about betrayal. It’s just that hunting for the real Philby is like wandering around a maze uncertain if you’re looking for the entrance or the exit.

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.

When asked about sex, the newly famous Boy George cocked an eyebrow and said he’d rather have a cup of tea. He was actually at it with the drummer. Compare and contrast with Cliff Richard, into whose afternoon beverage a vat of bromide was dumped somewhere back in the Fifties. His songs have reeked of sexlessness ever since. All that mucky business involving eager groins and sweaty throbbing is not really his department.

Directed by a Frenchmen, Foxfire adapts an American book to create a film with an archetypical stance and setting which could rank it alongside The Outsiders, Stand by Me or even Rebel Without a Cause. The problem is that despite depicting a passionate, wayward and issue-fuelled gang, Foxfire is not animated enough. It unfolds in deliberate steps, like a stage play. The young women may be on fire, but the measured approach of the overlong film tempers their spirit.

If ever there were a week for London to celebrate Poulenc in the lamentably under-commemorated 50^th anniversary year of his death, this is it. Two major choral works and two fun concertos at last join the party. But if Figure Humaine and the Concerto for Two Pianos look like being well positioned in the BBC Symphony Orchestra’s Barbican programme on Saturday, Yannick Nézet-Séguin’s chosen two were the victims of his own success in Prokofiev interpretation.