Supporters include Thames 21, Peter Ackroyd, the RYA and Olympic kayaking champion Tim Brabants (see more here).
How can such a project be controversial?
Well it is, and for two reasons. Firstly cost: as you'd imagine a 32 km long tunnel 75 m underneath the Thames does not come cheap - in fact estimates are around £2.2 billion. And this is going to come from just one source - residents of London through higher water bills.
The second is that access is going to be required to water front or adjacent locations from which bore shafts can be constructed through which to drop machinery and extract soil. And quite big machines and quite a lot of soil.
To give you an idea of the scale, the figure above from Thames Water shows a cross section in which fits three London double decker buses.
In fact "Thames Water anticipate that for the Main Tunnel Drive Shafts the typical construction duration is 6 to 7 years with indicative peak HGV traffic movements of 120 vehicles per day." (*)
You can see that this might not be popular.
So the Borough of Hammersmith and Fulham, which is currently the proposed start point of the tunnel, are raising objections - "Super sewer crater opposed". But they won't be alone - the report suggests that secondary sites will have to be located all along the river.
Watch this space, as they say.
(*) See this Wandsworth Council Planning Report, 1st March 2010.