There was a great sense of anticipation in the auditorium at the Watford Palace Theatre on Tuesday night as the members of the press settled in to their seats to watch the premiere of An Intervention: it’s the latest play from Mike Bartlett, so that was exciting enough anyway; it’s a co-production between the Palace and Paines Plough, who brought us last spring’s award-winning and brilliant Jumpers for Goalposts; and it stars Rachael Stirling, who graced the stage here in Medea (adapted by Mike Bartlett) in 2012 and recently starred in ITV’s The Bletchley Circle, and John Hollingworth, who returns to Watford after Our Country’s Good, also in 2012. And, on all fronts, it delivered.

Directed by James Grieve, An Intervention charts the friendship of the two characters played by Stirling and Hollingworth (they aren’t named, merely referred to as A and B in the script).

They met at a party and instantly clicked and now they are best friends. In the early days, they are almost a comedy double-act (indeed, Morecambe and Wise are evoked through most of the action taking place in front of the red-lit, closed theatre curtains) – they bounce off each other and, as Hollingworth’s character puts it ‘did things for each other; she energised me and fired me up, and I soothed her, steadied her, I think, and gave her perspective’.

But then Stirling discovers that Hollingworth supports the UK’s intervention in a Middle Eastern country that she has just been out protesting against, and after that we watch the relationship slowly unravelling, with Stirling’s increasingly apparent drinking problem playing no small part in its demise, and with Hollingworth’s relationship with the off-stage Hannah banging in the final nail in the coffin.

The overtly simplistic set design by Lucy Osborne – a bare stage in front of the curtains and a black room with just a table to denote a pub or an easel to suggest an art gallery – are the perfect antidote to the quick-fire, crackling dialogue and the electric performances from the two stars. And the musical selections, from Tom Gibbons, are perfectly placed.

The ending is very powerful – dramatic yet retaining the comical nature that the relationship was founded on. I can’t tell you what happens, of course, but suffice it to say that An Intervention more than lived up to all our expectations. Super stuff.

(Four stars)