It all started with The Railway Children. York Theatre Royal's adaptation of E. Nesbit's 1906 children's novel first appeared in York in 2008, before returning for a second season in 2009 and transferring to London the following summer. A second London season, which opened in June 2011, had its final performance this Sunday just gone.

Since that show arrived in a haze of smoke, steam and five-star reviews, stage adaptations of classic children's books have been all the rage. Autumn 2010 saw the openings of Matilda and Swallows and Amazons at the Courtyard Theatre, Stratford-upon-Avon and the Bristol Old Vic respectively. A year on – during which we were treated to a new production of Nigel Williams's 1995 adaptation of Lord of the Flies at the Regent's Park Open Air Theatre – and both shows are playing in the West End, having been lauded by the critics.

And there's more in store for 2012. While Swallows and Amazons heads off on tour and Matilda merrily rakes in the cash with bookings being taken up until October, the theatre world will be holding its breath for news of the Sam Mendes-directed Charlie and the Chocolate Factory rumoured to be coming to the Palladium later in the year. There are no confirmed details of the production available yet, but with music and lyrics by Tony Award-winners Marc Shaiman and Scott Wittman (the team behind Hairspray) and book by David Greig, it's an undeniably exciting prospect.

But what it is about adaptations of children's books that is proving so irresistible to both audiences and critics? Of course it's partly down to the magic of the original stories, as well as to the excellence of the shows themselves, brilliantly ambitious work by some of UK theatre's brightest stars (and supported, in the case of The Railway Children, Swallows and Amazons and Matilda by public subsidy). But there's more to it than that.

This genre of work is doing so well at the moment, I'd argue, because it represents the ultimate nostalgia-inducing escapist treat. These shows are not just popular with the family audiences for whom they were created, but also with adult theatre-goers who normally wouldn't dream of booking tickets for a 'family show'. And this next bit is unscientific, but I've also noticed that lots of the people getting excited about this type of show are irregular theatre-goers. I was amazed to see the enthusiasm with which some friends of mine who never ever go to the theatre discussed Swallows and Amazons, for example.

It seems that in the current climate of economic doom and gloom and social discontent, there's just something irresistible about spending a couple of hours immersed in a well-loved story from our childhoods. Even the eye-wateringly high West End ticket prices of some of these shows (ahem, Matilda) isn't enough to put people off.

Good theatre is always escapist to a degree but these shows offer an additional draw. Not only do they evoke memories of childhood – the simpler time when we first discovered these stories for ourselves, long before any notion of the challenges of adult life – but they also present worlds in which good conquers evil and friendship and imagination win out (although of course all the stories I've mentioned, except perhaps Swallows and Amazons, do have their dark sides).

The economy may be stagnating, heating bills may be soaring and riots may be breaking out on our streets, but perhaps we should be thankful, because after all, without the Tories, there'd be no need for all this wonderful theatre.