As it stood, the tunnel was only 'finished' in March 1861 although, at the time, it was exposed rock without a brick lining and required further work to complete it. The long approach cuttings were also unfinished at this time.
In March 1861, the tunnel was deemed complete with bare rock and no brick lining; it still required additional construction. Likewise, the long approach cuttings were unfinished at that time.