Tim Firth’s Sign of the Times – not to be confused with Jeremy Kingston’s long ago play of the same title which starred Kenneth More – started out as a one-acter at Scarborough in 1991 and has wound its way, a little limply, into the West End after touring last year.

It makes for a fairly agreeable short evening in the company of Matthew Kelly and Shameless star Gerard Kearns (the complete cast) but not a wildly exciting one. And the new, inferior second act doesn’t really develop from the first except as an inverted variation of it.

The play gently explores the give and take in a top dog and sidekick situation, starting on the roof and moving inside to an office three years later where the roles are not exactly reversed but reapplied; from putting up letter signs on a Batley rooftop, Kelly’s Frank has moved down in the world while Kearns’s Alan has become an assistant trainee manager in an electrical superstore.

From the author of such popular hits as Neville’s Island, the musical Our House and Calendar Girls on screen and stage, this must be counted small beer indeed. Peter Wilson’s production – nicely designed by Morgan Large – is touted as “an acutely observed human comedy about the art of achieving happiness in unpredictable times.”

That’s not how it comes across, more a niftily crafted low-key comedy of status anxiety and job prospects. Kelly’s secret life as an espionage novelist – he’s working on “The Spy Who Went Out in the Warm” – is levered in with Kelly demonstrating his campily inflected, throwaway comedy style, but not hitting any great heights, as he did in Of Mice and Men and, especially, Who’s Afraid of Virginia Woolf?