THE first thing with Dario Fo's popular farce is that you need to find

the right maniac. It is the central part in the play, the maverick who

turns impersonator to turn the interrogation screw on the police after a

suspect falls to his death from a fourth-storey window. Cast that role

successfully and the rest should flow along into, well, more or less

happy anarchy.

Craig Ferguson has joined the Arches Theatre Company for this summer

season political pantomime to reflect the resumption of bombings,

dubious suicides and scandal in Italian cities. Not that the play ever

seems exclusive to the Italian judicial mess, as the maniac's references

to the Birmingham Six, the Guildford Four and the Rodney King trial in

Los Angeles make clear.

Ferguson lends a stand-up comedian's ease to these apparent departures

from the script, and his readiness to offer audience asides creates a

nice illusion of total ad-lib. He possesses a range of popular theatre

skills that are essential to Fo, and he has just that right sediment of

anger that the author insisted should accompany the laughter.

Ross Stenhouse, Grant Smeaton and Raymond Burke give hilarious support

as the trio of oafish police trying to work out a plausible ''suicide''

scenario, and director Andy Arnold camps it up as a pedantic inspector.

It is a show which makes a neat virtue of economy, with the trembling

set design to add ludicrousness. A roller blind rolls down two storeys

of Milan skyline to get us from one office to another, and Ferguson

throws in the line: ''Mind your head on that building'' when Inspector

Pissani brushes alongside it. It is a portable city, and they are taking

it to the Assembly Rooms for the Edinburgh Festival fringe after this

run finishes on August 14.