A spokesperson for the council said:
"We cannot comment on particular cases but can confirm that CRB checking is a requirement of our transport provisions in relation to adults travelling on home-to-school transport in the capacity of an escort.Can anyone make any sense out of this?
"This is a standard requirement and has been for several years.
"Any adult acting as an escort will, in the public gaze, be viewed as acting with the full acquiescence of the council and hence with its implied authority.
"For the protection of the council and all vulnerable persons in its care it's essential all those endowed with an authority, implicit or explicit, should meet the security requirements within the transport contract provisions."