The £4.2bn Thames Tideway super sewer has been awarded planning consent by Government and is on course to start construction in 2016.

Next step for the project is to reach financial close and gain a licence from Ofwat for the new company - Thames Tideway Tunnel Ltd – being set up to build operate and own the scheme. This is hoped for in summer next year but may be delayed by the election until October, according to Thames Water in its current negotiations with the water regulator over its AMP 6 spending period determination.

“If the tunnel had been in operation last year, it would have captured 97% of the sewage that poured into London’s river,” said Thames Tideway Tunnel chief executive Andy Mitchell.  “We are pleased we can now start to tackle this archaic problem."

The planning decision announced by Communities Secretary Eric Pickles and Environment Secretary Elizabeth Truss said that “the basis that the national need for a Thames Tunnel has been demonstrated”.

The 25km tunnel will run underground from Acton in West London  and travel roughly the line underneath the river to Abbey Mills Pumping Station in East London. The planning decision gives approval to start construction work at 24 sites along the way.

However there may yet be a legal challenge from Hammersmith & Fulham Borough Council over use of a brownfield site at Carnwarth Road which the council claims will cause misery for residents. 

Last year 55M tonnes of sewage polluted the tidal River Thames, far higher than the average 39M tonnes that discharge in a typical year. This was due to exceptionally wet weather which caused London’s combine sewerage system overflow into the river more than normal.

“If the tunnel had been in operation last year, it would have captured 97% of the sewage that poured into London’s river,” said Thames Tideway Tunnel chief executive Andy Mitchell.  “We are pleased we can now start to tackle this archaic problem."

The tunnel will have an internal diameter of between 6.5m and 7.2m, at a depth of between 35m in West London and 65m in East London.

The scheme is expected to take seven years to build and will complete in 2023.

“A great deal of expertise in tunnelling has been developed over the past five years as Crossrail has progressed and this project will safeguard that specialist skill base can continue operating in the UK. It is essential that government do its utmost to line up projects in this fashion, limiting the gaps in project pipelines that would result in this highly skilled workforce moving overseas," said ACE chief executive Nelson Ogunshakin, welcoming the Government’s decision. 

Infrastructure Intelligence editor Antony Oliver spoke to Thames Tideway Tunnel chairman Sir Neville Simms earlier this year.

How do you describe your role?

I have been hired to set up Thames Tideway Tunnel Limited, the new infrastructure provider company that will construct and operate the new Thames Tideway Tunnel. My key task is to build a team. A team that is credible and competent to future investors and that can demonstrate it is capable of picking up this important project and delivering it on time and to budget.        

The delivery structure is very different from other privately financed projects. How do you describe it?

I like to describe the project as having a ship and dock structure – Thames Water is the dock in which the new Thames Tideway Tunnel Limited infrastructure provider is constructed. When the time is ready, planning consent is granted, operating licenses are agreed with the regulator Ofwat and investors are in place, the new ship will sail out of the dock and become a new independent company. At this point the only link with Thames Water will be via a series of commercial contracts, including for operation and maintenance of the tunnel asset.

How does Thames Tideway Tunnel Limited interface with the Thames Water team now developing the project?

We work in partnership with the Thames Water and CH2M HILL teams, working to influence the decisions – without specifically having accountability but knowing that we will be responsible for the project’s successful construction and operation later.

What do you see as the critical risks to manage?

On a project like this there are two main risks that investors will look at. The first, of course is construction risk – can we deliver the construction programme to time and to budget? My task is to put together a team that can give investors the confidence that this will happen. The fact that we will be following directly from a very successful Crossrail delivery will only help. The second risk for investors is how much will their investment be able to earn and over what period.

Read the full interview here