Thames Water has extended its 14-week public consultation on the Thames Tunnel by almost a month to give people more opportunity to have their say. A two-day public exhibition will also take place at City Hall.

Since the consultation started in September, Thames Water has sent out 175,000 letters to potentially affected communities, staged over 20 local 'drop-in' exhibitions close to potential sites and attended over 40 other meetings. More than 4,000 people have attended exhibitions so far and 1,000 people have already submitted their feedback. The new closing date for comments is 5pm on Friday 14 January 2011.

The proposed 20 mile long Thames Tunnel sewer is urgently required to tackle the 39 million tonnes of sewage discharged into the River Thames each year.

It will collect the sewage currently discharged to the river from the 34 most polluting combined sewer overflows, to capture sewage which otherwise discharges into the River Thames, before transferring it to Beckton Sewage Works for treatment.

The combined sewer overflows were designed by the Victorians as a safety feature to prevent the sewers from backing up into streets and gardens when full. Used only occasionally in the 19th century during a heavy storm, the overflows can now discharge sewage into the river after as little as just 2mm of rainfall which is happening just over once a week on average.

Phil Stride, Head of London Tideway Tunnels, at Thames Water, said:

"To find the least disruptive and most cost effective route and sites we need to listen very carefully to everybody's views.

"Feedback indicates some people have only recently become aware of the consultation. That’s why we’ve decided to give people more time to get their comments in to us.

"No final decisions have been taken yet. We are following up new information which has been provided by local people and will carefully consider all comments and suggestions. Where possible, we will amend our plans. These revisions will form the basis of the second phase of public consultation which will take place next year."

The remaining exhibitions will be held at:

• Barnes: Monday 6 - Tuesday 7 December, 10am - 8pm WWT London Wetland Centre, Queen Elizabeth's Walk SW13 9WT
• Southwark: Monday 13 - Tuesday 14, 10am - 8pm City Hall, The Queen's Walk SE1 2AA

The target date for the submission of the planning application is mid 2012. Initial construction of the Thames Tunnel is provisionally scheduled to start in 2013 with programmed completion in 2020.