Hobson'S Conduit

Hobson's Conduit

Hobson's Conduit is a water distribution system of medieval and later origin. The conduit head originally stood on Market Hill but was re-erected in its present location on the corner of Lensfield Road and Trumpington Street in 1856.

The system originally comprised four channels from the conduit head, three of which existed in the 17th century. One channel continued east along what is now Lensfield Road and St Andrews Street, with its open watercourse clearly visible in Horraden's map of 1810. A second flowed north-eastwards to the fountain in the Market Place, although this was cut off near Downing Street in 1970 when the Lion Yard was redeveloped. A third flowed in the open behind the first three houses in Trumpington Street, ran through a brick culvert behind Cromwell Lodge and then emerged in the open at Addenbrookes before being piped under the pavement of Trumpington Street. A stretch of this channel was abandoned around 1905. With the exception of a small section in St Andrew's Street, all these channels are now piped or run in culverts with no evidence above ground except for manhole covers and plates.

In the 17th century a Hobson's Conduit channel appeared to have taken the route via Addenbrookes before continuing down the middle of Trumpington Street. It then turned off to the left down Mill Lane at the gate of Pembroke College and flushed out the King's Ditch with a subsidiary channel round the back of Pembroke College, falling into the King's Ditch to the west of Free School Lane.

Henry Gunning's reminiscences, published shortly after his death in 1854, provide a description of the watercourse in 1794. He recorded that along the whole front of Pembroke College was a watercourse that divided the street into two very unequal parts. The west side was necessarily the carriage road but was only one-third the width of the road which adjoined the college and was appropriated for foot-passengers. The sides of the channel were boarded and it was crossed by two very narrow bridges, one opposite the Master's Lodge and the other opposite the gate of the college.

When the change to the present arrangement of twin runnels occurred is not known exactly. In 1789 it was agreed that the town should widen Trumpington Street by taking in a strip of the street frontage to which Pembroke College had a claim, which suggests that even before 1794 works to the street were envisaged. Custance's map of 1798 fails to distinguish either the channel or the two runnels, but it is likely the change would have taken place by then, probably soon after 1794. The two runnels were definitely substituted before 1815, the date of Ackermann's engraving of Pembroke College which shows them.

W. D. Bushell refers to the runnels originally welling up opposite the north end of Addenbrooke's Hospital front rather than the present location in front of Brook House, citing as evidence an unnamed plan of 1832. There is some evidence that may relate to this on the ground where the kerbstones to the north of Addenbrookes are broader than those to the south, although these larger stones may simply be a result of subsequent resurfacing of the road or pavements. Certainly when the conduit was surveyed in 1886, the resulting plans showed the present arrangement of the runnels commencing at Brook House. The conduit works have subsequently undergone minor alterations, the runnels being piped under side roads.