6.5.1 It is not always possible to ascertain who holds an interest or beneficial interest in shares and it may not be possible in any event to police more remote changes of ownership. The use of nominees means the Authority may not even be aware of changes. The protection offered by change of ownership provisions should therefore be seen by the Authority as an important but imperfect tool for controlling the substantive ownership of its counterpart. Transparency of ownership is however taken very seriously by the public sector and Contractor groups must not attempt to disguise the effective beneficial ownership of the Contractor.