9.2. Where the entrance to or exit from any platform or station is via an
automatic ticket barrier no person shall enter or leave the station,
except
with permission from an authorised person, without passing through the
barrier in the correct manner.

If there is no staff around and your ticket is rejected, can you follow
someone through or go through the luggage rack? Also, can you enter by an
(unlocked) side gate if your ticket is Rejected.
--
To reply direct, remove NOSPAM and replace with railwaysonline
For Train Information, The Latest News & Best photos around check out the
Award Winning Railways
Online at http://www.railwaysonline.co.uk