6. Where a child has been removed to a place of safety by a constable under section 61(5) of the Act, a constable keeping him in a place of safety shall, subject to subsections (6) to (8) of that section, continue to so keep him only so long as he has reasonable cause to believe that–
(a)the conditions for the making of a child protection order laid down in section 57(1) of the Act are satisfied; and
(b)it is necessary to keep the child in a place of safety in order to protect him from significant harm (or further such harm).