In Christmases past, the MacRobert's splendid Playhouse children's studio has hosted shows for the very young by such outstanding artists as Oily Cart theatre company and Andy Manley.

Theatre-makers such as these are hard acts to follow, and Polar Molar (an in-house production, written for kids aged three and upwards by Abigail Docherty, and devised collaboratively with the actors, director and designer) does not really measure up.

One is surprised, as well as disappointed, by this, as the team behind this show (Docherty, Julia Innocenti, Ros Sydney, Lu Kemp and Karen Tennent) are the creators of the justifiably acclaimed children's piece One Thousand Paper Cranes.

However, there is a sense in which Polar Molar (in which mad explorer Captain Scot Scott and his trusty husky DogBog go off, in the year 2020, in search of the last polar bear) is a victim of the previous show's success. One Thousand Paper Cranes – which took as its subject the nuclear attack on Hiroshima on August 6, 1945 – was a brilliant example of an issue-based production which, nevertheless, put the requirements of drama before the more didactic demands of politics and history.

Crucially, that piece was made for schoolchildren. In trying to transfer the formula to a younger audience, Docherty and Co have ended up with a somewhat lop-sided show. Certainly, the interior of Captain Scot Scott's snow mobile looks great, and the little mittens handed to the children as they enter the theatre (so they can pretend they have husky pup paws) are a lovely touch.

However, the moments of audience participation never really get close to the Oily Cart-style interactivity that truly engages three-year-olds, and the series of events (from a walrus returning the Captain's carelessly discarded plastic bottles to DogBog's environmental rant) is simply too polemical.