Olivier award-winning actor David Haig has successfully forayed into the world of script writing before now, with the highly acclaimed My Boy Jack – a work that was turned into a TV drama starring Haig alongside Daniel Radcliffe. Haig is also the star of his latest play, Pressure, and again we are on the topic of war, but this time from the relatively humble position of meteorologist Group Captain James Stagg, the Scottish expert who defied the opinion of the American weather forecaster to advise Eisenhower to postpone the D-Day invasions of 1944, thus saving an estimated 80,000 lives.

Currently running at The Park Theatre in North London, this quality Royal Lyceum Theatre Edinburgh (where it premiered in 2014) and Chichester Festival Theatre production is directed by John Dove who is fresh from the wonderful Farinelli and the King starring Mark Rylance which has just opened on Broadway to more rave reviews.

The entire action of Pressure takes place inside Southwick House in Portsmouth, the HQ of the allied expeditionary force where General Eisenhower (Malcolm Sinclair) headed up what was to be the largest amphibious landing in history. We Brits famously like talking about the weather, and this play is utterly devoted to it if you do, as is the set with its large backdrop of regularly updated weather charts which Stagg must analyse (Designer Colin Richmond), ever conscious that 350,000 lives depend upon the accuracy of his judgement.

Haig’s Scottish accent is unconvincing no matter how many times he says ‘aye’ (and that’s a lot) but it’s rather like watching Tony Hopkins as Picasso or Nixon, and therefore doesn’t detract from what is a strong performance of the gloomy Scotsman whose temper runs increasing high as he feels the weight of his role during a pivitol moment of the war.

Aside from the fact that Stagg’s wife (whom we don’t see) is about to give birth with possible complications if her last child is anything to go by, there is very little plot aside from whether or not Operation Overlord will proceed at the intended hour. Anyone who knows their history will already be aware of the punchline, nor do I know who thought of describing Pressure as a thriller, as save for the odd clap of thunder there isn’t much in the way of thrills.

Philip Cairns is amusing at the suave Irving P. Krick, the American meteorological consultant whose reputation was based on having correctly judged when to film key scenes in the 1939 Hollywood blockbuster, Gone with the Wind. Sinclair is meanwhile engaging as Eisenhower, while Laura Rogers puts in a steely yet compassionate performance as Stagg’s right hand woman Kay Summersby, the only female member of the cast.

There are bright spells of humour about the unpredictability of British weather and the dialogue is nicely written overall, with the exception of a few trite turns of phrase that should have been ironed out, and though the almost constant barrage of meteorological terms shows how thoroughly Haig has researched the subject, it’s at the cost of erring on the tedious. Unfortunately Pressure never goes beyond being a pleasant, enjoyable evening of theatre and, without offering the gripping wartime tension or power I was expecting, left me feeling rather deflated.

Pressure at Park Theatre, Clifton Terrace, Finsbury Park, London N4 3JP from 28 March until 28 April 2018. Running time approximately 2 hours and 10 minutes including an interval. For more information and tickets please visit the website.