John Gay’s 1728 satirical drama was the first ballad opera. The vernacular work not only cocked a snook at the Italian operas that were so in vogue in 18th-century London, but it also lampooned Whig politician Sir Robert Walpole and the British love for scoundrels. It was an instant, huge hit; as a witticism of the time had it, The Beggar’s Opera made Rich gay, and Gay rich.

Sometimes people leave you halfway through the wood. Sondheim meant that in a life-and-death kind of way, but it applied literally to this ingenious show at the autumnal August preview I attended. Some folk thought Act One’s knitting-up of polyphonic fairy-tale lines really was the happy end. Others found unseasonable damp gnawing their bones and slunk off to comforting warmth. Don’t go, I pleaded, it gets deliciously darker.

Usually a seasonal home for the pastel-coloured delights of drawing-room farce, musical comedy and the odd Shakespeare pastoral, Regent’s Park Open Air Theatre is this year offering a programme of rather darker hue. With Macbeth to follow later in the season (not to mention Stephen Sondheim’s deliciously off-white fairytale musical Into the Woods) it was with a new production of Arthur Miller’s The Crucible that things kicked off last night.