the construction of Southampton Tunnel was the only realistic choice, as a surface alignment would have severely impacted the planned development of parkland around Southampton. The tunnel had originally been proposed as being just in length, but during the parliamentary stages, to avoid compromising the towns plans to convert the Lamas Lands to parks, a longer tunnel of was agreed upon. The route selected for the new tunnel cut through that of the Salisbury and Southampton Canal tunnel, an earlier project that had been abandoned four decades before. Early reports by the railway's engineer suggested it might be possible to use the canal tunnel in some way for the construction of the railway but by the time the bill for construction was placed before Parliament this idea had been rejected and a new alignment with a shorter tunnel was proposed. The Southampton and Dorchester Railway's railway's engineer was William Moorsom and the contractor for the construction of the line was Samuel Morton Peto through his company Messrs Grissell and Peto. It was decided to construct the majority of the tunnel using the traditional cut-and-cover method, with only a limited section (the portion running directly underneath the London Road) being actually bored out. Experienced miners from Cornwall were recruited for the project as their specialist skills were valued for the bored section. The pre-existing incomplete canal tunnel crossed the intended route of the new railway tunnel at an acute angle and a slightly lower level near their western ends. A contemporary scale cross-sectional drawing dated June 1847 shows that, close to the point at which the two tunnels met, the base of the canal tunnel was only slightly lower than that of the railway tunnel and that the level of the water it contained was at a similar level to the base of the new tunnel. The canal tunnel had itself proven difficult to construct, with various sections sinking or collapsing due to geological conditions, poor materials and improper supervision of the works. It became apparent that the canal works had compromised the ground considerably, and despite removal of a section of the older tunnel where it was crossed by the new structure, geological problems accentuated by heavy rain and hard frosts in 1846/47 plagued the railway tunnel's construction. Buildings in the vicinity of London Road (later Above Bar Street) suffered subsidence and there were concerns expressed about the state of