Engineers from Thames Water have planted drilling equipment in the River Thames by Hammersmith Embankment to establish if the area is suitable for super sewer construction.
The firm will drill underwater boreholes to test the soil condition ahead of its decision on whether to choose the embankment as one of the construction sites it needs to build the 20 mile-long, underwater tunnel.
It wants to use the embankment to house a huge shaft from which digging machinery can be mobilised during the sewer's construction, which is expected to take at least four years.
The tests have sparked yet another row between Thames Water and Hammersmith and Fulham Council, which has accused the utility firm of failing to inform it of of the tests.
It was already furious with the company over its plans for another site, Carnwath Road in Fulham, which Thames has earmarked for several more shafts, having previously considered the area too small.
Now the council has branded Thames 'arrogant and aggressive' for not informing residents of the digging tests.
However, a Thames Water spokeswoman explained: "The council gave us permission earlier this year to use the rig on the agreement we send notification letters to all properties within a 125-metre radius of where we are working.
"There are no properties within that proximity to the rig's current location, so no letters have been sent out."
But deputy leader Nick Botterill blasted:"This lack of consultation seems to be a reoccurring theme from Thames Water
"First they got criticised for not notifying enough residents about their Fulham U-turn and now they have brought in a large rig to Hammersmith without telling anyone."
He added: "While Thames Water might not like the fact that increasing numbers of local people are against their plan this is no excuse for treating them with contempt."
