A Midsummer Night's Dream (Royal Shakespeare Theatre, Stratford-upon-Avon)

The RSC is embarked on a touring production of The Dream involving amateurs as the mechanicals, "hard-handed men… who never laboured in their minds till now"; great idea, in the quarter-centenary year of the Bard's death, but it was hard to tell last night any great difference between the Nonentities of Kidderminster (as Bottom and co) and the nonentities of the RSC (as the lovers and fairies).

The Dream is nothing if not sexy, and this one's not even wet. Where's the spark of an RSC stalwart or star in Erica Whyman's production? Why does the show take half an hour longer than it should because no-one can skim and breathe properly across the verse? Why does fairyland look like a 1980s re-heat with a grand piano as Titania's bower, Puck in a top hat (please!) and fairies in vintage clothing and messy hair-do's?

The momentum's all wrong, too, especially in the quarrel scene, Hermia denied the pay-off line ("I am amazed and know not what to say"), while Oberon (Chu Omambala, a cool dude in a white suit, no shirt) cedes his final speech to a crowd of inaudible school-kids, supposedly Titania's train but in effect her pointless hangers-on in school uniforms.

At least Omambala has something of a voice. The Helena and Hermia of Laura Riseborough and Mercy Ojelade are correctly contrasted in height but are bland and badly articulated; nor are they helped by their clunky heels banging on the bare boards stage (design by Tom Piper). The atmosphere here is loosely 1940s war-time, with an onstage jazz band, Egeus (a dyspeptic Peter Hamilton Dyer) kitted out as an RAF officer and the interchangeably perky Lysander and Demetrius of Jack Holden and Chris Nayak sporting suits and V-necked short-sleeved jumpers.

In respect of the mechanicals, the RSC thinks that The Dream is a love-letter to am-dram. In many ways it is: things go wrong, good intentions are subverted by incompetence and made fun of as in Michael Green's Coarse Theatre. But the thing about playing the trumpet or piano badly – as Max Wall and Les Dawson demonstrated – is that in order to make the musical mishap funny you have to be able to play it well in the first place.

Drama teacher Chris Clarke's broad Brummie amateur Bottom – on the stage where David Waller in a string vest and red nose gave one of the greatest Bottoms of all time in Peter Brook's production – is okay until he goes a bit too camp in Titania's bower (that's the grand piano, natch) and then starts thinking we really want to enjoy his company.

The star of the "Pyramus and Thisbe" play is Alex Powell's febrile, flailing Flute, hurtling onto the stage in the dazed panic of one who really would speak his lines, cues and all, in one gulp. But having set up the chink in the "wall" as the gap between Snug's legs, bad timing ruins the gag they've so carefully prepared: "I kiss the wall's hole, not your lips at all." Sue Downing is a perfectly affable Peter Quince, but she's ineffective as a fusspot or stage manager.

The RSC is collaborating with fourteen am-dram companies and hundreds of schoolchildren in this "play for the nation" project but, at the moment, it looks as though social and political priorities, excellent in themselves, have overtaken and eclipsed artistic achievement. I look forward to taking another rain check later in the run.

A Midsummer Night's Dream is in Stratford-upon-Avon until 5 March, then touring until 4 June.

Read all about the amateur Bottoms in our recent feature