Abstract: Concealed fire detector suspension apparatus has a fixing collar and a plurality of radial locking tabs insertable therethrough. A removeable fixing foot is configured for engaging a stem of an upright support for a fire detector and having a peripheral outward locking formations which mechanically interlock with corresponding inward locking formations on an inner surface of the fixing collar. In use, the apparatus is configured for installing the fixing collar via a ceiling cutout, inserting the radial locking tabs through the fixing collar from the interior thereof to clamp the ceiling, inserting the upright support through the fixing collar and locking the outward locking formations of the fixing foot to the corresponding inward locking formations of the cylindrical body, thereby supporting the upright support through the ceiling.