During construction, the tunnel was flooded on six separate occasions the worst being the second flooding, on 12 January 1828, in which six workmen died.
"Near shift change. Isambard was in the shield, helping workers at the face itself. “Suddenly a torrent of water swept in, knocked them out of the frame and extinguished all the lights. A fallen timber trapped Isambard’s leg”".
Brunel was badly injured and from his diary "laid up quite useless for 14 weeks and upwards".