Sign of the Times ** TNT

It’s a shame to see two decent actors wasted in this trivial and inept comedy, which is stretched beyond credence from a single idea into a two act play with too many longueurs and too much clumsy plotting.

Initially we see middle-aged Head of Installation Frank (a nicely understated Matthew Kelly) trying to drum some sense of responsibility into reluctant work experience Alan as they erect a giant illuminated sign high up on the roof of the building where the former has worked for years. Loyal, old school Frank takes enormous pride in his work, even though he’d really rather be writing spy novels. Alan, on the other hand, couldn’t give a toss.

Three years later and the roles are more or less reversed, with Gerard Kearns’ Alan smartened up in a suit as befits his new role as electrical superstore trainee assistant deputy manager (though he still hankers after a career as a musician) and Frank on the scrap heap of the elderly unemployed, but still willing to learn.

Tim Firth (who wrote the script for the hugely successful film Calendar Girls) penned the first act two decades ago, added the second sixteen years later, and has since revised and renamed the combined result. Regrettably it’s ended up little more than a harmless but salutary reminder that sometimes it’s better just to let things lie.

Duchess, Catherine Street, WC2B 5LA (0844 412 4659) Tube: Charing Cross signofthetimeslondon.co.uk Till 2nd April (£21 -£46)