At the end of the interview don't let your guard down, you want the
  employer to continue viewing you positively, so thank them for the
  opportunity of the interview, for their time and consideration.
   
  Reiterate at this point if you are interested in the job and convey your
  interest. However do not seize this opportunity for after thoughts.
  Leave the room with any belongings and a firm handshake.
   
  As soon as feasibly possible contact your consultancy with feedback from
  the interview and if you have reached a decision (you may appoint the
  consultancy to accept on your behalf, if they have all the facts). They will
  in turn contact the prospective employer and respond to you accordingly.
   
  If the interview does not create a positive result, do not be despondent it
  is all experience for the future with added knowledge of your interview
  technique that may be improved or refined.
   
  Some people always seem to succeed better at interviews than others,
  it's not luck but simply preparation. All the preparation in the world
  will not guarantee your success but it might just help you get the job
  you want!