It is difficult to understand what drew director Peter Wilson to this insipid, lazy and sentimental play, but one has to admire the effort he and the cast have put into making the best of it. However, you can only work with the material at hand, and Tim Firth’s script is mostly excruciating. It manages to be both predictable and un-naturalistic, and the lines that Alan (Gerard Kearns) and Frank (Matthew Kelly) are given to speak leave them with such flat characters that it was difficult to muster the energy to care when they were in mortal peril.

The dialogue is clumsy and over-reliant on the (misguided) belief that having a Yorkshire accent is intrinsically funny. Do we really subscribe to such lazy stereotypes? The premise – that all Northerners are a bit thick and therefore funny – grates hugely, especially when staged in the West End of London. Kelly and Kearns deserve better.

And, to give credit where it’s due, Wilson does his best to elevate the script and to give them a bit more to work with. They try to flesh out under-developed and unsympathetic characters, but the words are lacking in wit, verve or energy – so that we never really care what happens to either of them. When Frank sort-of threatens to jump off the roof, there is no sense that the audience is tense, willing him not to jump. Firth fails to invest him with sufficient depth, and we don’t feel any emotional attachment to him. Likewise, when young Alan appears to be throwing away his dreams for a dead-end job, it is all to easy to shrug and head for the nearest bar.

Morgan Large’s design is great: the space is used cleverly, it is easy to believe that we are witnessing exchanges 60-stories above the ground, and the dilapidation of the building and surrounding Batley are convincing. Tony Simpson’s lighting and Gareth Owen’s sound are well-judged, and complement the drabness of story and setting.

There are some nice moments, but these are mostly down to Wilson’s judgement: the laughs come from well-time pauses, the odd lifted eyebrow, the interaction between Kelly and Kearns, rather than from the script itself. Despite these brief glimpses of humour, though, this comedy commits the biggest sin of all: it just isn’t funny.

Sign of the Times is playing at the Duchess Theatre until 28th May.