Theatre: A MIDSUMMER NIGHT'S DREAM Regent's Park Open Air Theatre, London

To some, Toyah Willcox will be best remembered for the frequency with which she changed her hair colour as a punky singer in the early 1980s. She even appeared in a Kenny Everett sketch where the hue of her barnet altered every second. Toyah's problem ever since has been to get people to take her seriously as an actress.

In fact, her shift into Shakespeare is not as incongruous as, say, the prospect of Johnny Rotten playing Hamlet. Although she is, as one casting- director described her "not one of our finest actresses", Toyah is far from being an embarrassment on stage. Take her performance as Puck in the sparky production of A Midsummer Night's Dream at the Regent's Park Open Air Theatre. With her impudent grin and lisping, little-girl's voice, she brings exactly the right mischievous quality to the role of the goblin. Dressed in a white sailor suit and with tight blonde curls as an apparent homage to Shirley Temple, she can caper with the best of them. Whether making spectacular entrances on skateboards, tricycles, roller-skates or penny farthings, or strutting around like Jacquline the Lad, or casting spells to music straight out of The Twilight Zone, she has a perky charm which helps wipe away all memories of albums with such cringe-making titles as Warrior Rock, Minx and Toyah! Toyah! Toyah!.

All right, so her performance is broad, but she has to grab the audience's attention in order to prevent them from dropping off and catching hypothermia. On Wednesday, we felt like extras in Ice Station Zebra - despite the presence of more tartan blankets and scarves than you see on a cold afternoon at Murrayfield. Your heart went out to the fairies, smiling through the pain as they scampered around in diaphanous blue vests. Maybe their enthusiastic cartwheeling was just a ploy to keep warm.

Outdoor theatre is often brilliant in theory, brass-monkeys in practice. Toyah's expansiveness is matched by Robert Lang's likable, bombastic Bottom pawing the ground and eeyore-ing as if he were at the starting-line of a donkey derby. Titania (Harriet Thorpe, better known as the receptionist who keeps her children in the desk-drawer in The Britass Empire) simpers at him with lusty conviction. And James Merifield, the designer - whose moonscape set is apparently inspired by the cover of a Yes concept album circa 1975 - displays a comparable exuberance.

There is a tradition of Dreams in Regent's Park - so much so that the bar serves a cocktail called Puck's Fizz. My memory might be playing tricks, but I have a dim recollection of the spooky spectacle of Christopher Biggins as Puck here a few years ago. John Doyle's production may not be the most polished ever mounted, but having to compete with advertising execs playing shouty softball nearby, birds tweeting in the trees and jets zooming overhead, how could it be? Actors performing outdoors need only one note from the director: Big is Beautiful.

n To 7 September, Regent's Park, London (Booking: 0171-486 2431)