Sandi Toksvig has written this comedy with the best of intentions but the piece turns out, in practice, to be a rather embarrassing reminder that every silver lining has a cloud.

The author has let it be known that the piece is a counter-blast against two aspects of society's treatment of the elderly – the abandoning of old people to loneliness and boredom in under-stimulating care homes, and the dearth of good parts for senior actresses who, after a certain point in their distinguished careers, become virtually invisible.

The author has, accordingly, fashioned a scenario that is designed to be a robust retaliation – marketing itself as “The Great Escape – senior citizen style”. We’re in the upper day room of the Silver Retirement Home in, er, Gravesend. The capital is experiencing freak floods (cue lashings of the thunder and lightning); the waters are on the rise; and six female characters – five of them inmates and one a very young black woman who was sent on the aborted rescue mission – gradually come to the conclusion that they been left to their fate.

“They’ve written us off. They think we’re not worth saving – well, bugger that. We may be old but we’re not done yet,” declares Gloria, an 86-year-old Cockney (played by Sheila Reid in leopard-print jump-suit and henna perm). Gloria has been secretly hoarding bits of her antidepressants against a rainy day. But faced with this insulting show of neglect by the authorities, she rallies and becomes a cheerleader of the sisters-do-it-for-themselves fightback that quite amusingly draws on the diverse areas of expertise (from martial arts to radio-ham know-how) that this bunch have built up over a life-time.

I wish I could say that Silver Lining works. But though it is sometimes clever, the play feels mechanical and lacking in real warmth. Rebecca Gatward – director of this co-production between the Rose Theatre and English Touring Theatre – has assembled a cast of distinguished veteran performers who could make deep music together, given better material. It includes Maggie McCarthy and Joanna Monro as May and June, a pair of bickering sisters – the former a wheelchair-bound lesbian, old BBC hand, and effectively moral centre of the piece; the latter a prejudiced Christian with a secret sorrow. There’s Rachel Davies as Maureen, a former actress, and Amanda Walker as a woman, nicknamed St Michael after her dressing gown label, who suffers from dementia and who clutches a wooden box that turns out to contain state-of-the-art sex toys. This character periodically emerges from her seemingly vacant state with little remarks about Greenham Common or Archimedes Principle that give us tantalising hints about her earlier life. All the inmates get their moment in the sun with soul-bearing monologues. But that delivered by St Michael, who is evidently not bitter that her memories are now dim and confused and who sees her current lot as a sort of peaceful respite – “I know everyone looks at me and wonders what’s inside but I’m fine with the space. I don’t mind just sitting. I had a lifetime of doing” – struck me as rather presumptuously written. Her solo speech must be meant to be reassuring; if so, it had the opposite effect on me.