Before the Plays That Went Wrong and the multi-role six-hander Operation Mincemeat, there was Patrick Barlow’s adaptation of The 39 Steps: four actors on a collision course with feasibility.

On opening night, there’s always a little tension in the air. Tech rehearsals and previews can only go so far – this is the moment when an audience, some wielding pens like scalpels, sit in judgement. Having attended thousands on the critics’ side of the fourth wall, I can tell you that there’s plenty of crackling expectation and a touch of fear in the stalls, too. None more so than when the show is billed as a new musical.

Five years ago, Rachel Parris tells us, she never thought she would one day be married, a mother and a home owner. Now she's all three – and a stepmother as well – and this year is about to turn 40. It's quite a journey, which she talks about in her new show, Poise.

For fans of a certain age the name Jack Docherty will always be associated with a very good run of chat shows on Channel 5; he was also the star of Channel 4's sketch show Absolutely and more recently the Scottish comedy Scot Squad. And now he's on the road with David Bowie & Me – Parallel Lives, a sort of memorial to lost youth but also the life-affirming joy of music.

Small-scale shows, nurtured in offbeat places, are becoming all the rage in the West End. Red Pitch, Operation Mincemeat, For Black Boys… have already made their mark, and now this quirky musical for just two performers joins them.

If you don't like sweary comics – Jonathan Pie uses the c-word liberally – then this may not be the show for you. In fact if you're a Tory, ditto, because it is 70 minutes of political invective, taking aim at a rogues' gallery of senior Conservatives present and past. Oh, and the royal family get it in the neck too.

Shakespeare’s plays have ever been meat for masher-uppers, from the bowdlerising Victorians to the modern filmed-theatre cycles of Ivo Van Hove. And Sir John Falstaff, as Orson Welles proved in Chimes at Midnight, can be the star of his very own remix, bestriding three plays and dying offstage in a fourth. 

Memory is a confounding thing. By way of proof, just ask the Mary Tyrone who is being given unforgettable life by Patricia Clarkson in London's latest version of Long Day's Journey into Night, which has arrived on the West End (and at the same theatre) a mere six years after the previous version of Eugene O'Neill's posthumously premiered masterwork; that one headlined a top-rank Lesley Manville in the same part.

Is there a more purely likeable actress than Sheridan Smith, the performer who was still a teenager when she stole the show at the Donmar in Into the Woods and who managed, as Elle Woods in the West End premiere of Legally Blonde, to bring tears both to her eyes and ours?

In a secret chamber somewhere, the producers of MJ the Musical may be keeping a portrait of the King of Pop that has acquired all his scars, physical and psychological.