No child under 14 years of age (other than an infant in arms) shall be permitted to be present in court during the trial of any other person charged with an offence, or during any proceedings preliminary thereto, except during such time as his presence is required as a witness or otherwise for the purposes of justice; and any child present in court when under this section he is not to be permitted to be so shall be ordered to be removed:

Provided that this section shall not apply to messengers, clerks, and other persons required to attend at any court for purposes connected with their employment.