UPDATE: A spokesman for South West Water has said that it is possible but not definite that work will start in April 2013 and take up to 60 weeks.

She said SWW was in discussions with Cornwall Council, Truro City Council, the Business Improvement District, local traders and bus companies but that the sewerage network in parts of Truro is no longer able to cope with the demands placed on it.

Adding: "There are currently 23 properties at risk of internal sewer flooding and five at risk of external sewer flooding in the city centre.

“We are in the process of designing a £3 million scheme to upgrade the network, which will involve replacing the sewers in Frances Street, Kenwyn Street and Little Castle Street with bigger pipes.

“It is possible but not definite that work will start in April 2013 and take up to 60 weeks to complete. 

“We are aware that this essential work will cause disruption in the city which is why we will be working closely with the local community to put in place measures to minimise the impact of our works.”

The plan has been called potentially “catastrophic” for Truro traders, who could face months ofdisruption due to plans to dig up large parts of the city centre for the sewerage work.

Letters sent out to members of Truro Business Improvement District by BID manager Neil Scott warn that South West Water, through its contractor Balfour Beatty, has “confirmed its intention to undertake a major project of works to relay new sewerage pipes to the west of the city centre”.

The work would entail the complete closure of Victoria Square, Kenwyn Street and Little Castle Street, with, significant changes and disruption to the other roads in the vicinity.

In the letter Mr Scott said: “There are circa 60 businesses currently trading in these areas, and the impact of closing the roads to all vehicles for such a time span, coupled with the added severe disruption caused by the actual works, will potentially be catastrophic to businesses in the area, in what is already a very difficult economic climate.”

He added that the two main impacts would be on access by vehicles to service businesses and customer vehicles, as well as the “significant impact on pedestrian flow to these areas”.

With an “urgent need to find out more” about the proposed works and how to respond to them, a meeting has been arranged on Monday, January 16 at 6pm at The One Eyed Cat on Kenwyn Street.

Both South West Water and Balfour Beatty will be invited to, “provide evidence that the works are essential, to request alternative solutions and hear how they intend to support the affected businesses”, during the work.