London sewer blocked by 105-tonne ‘concreteberg’
A record-breaking 'concreteberg' as heavy as a blue whale has been discovered in a north London sewer.
The blockage, caused by people pouring concrete into drains, is the largest that water company Thames Water has ever seen.
Over time it has built up to become at least 100 metres long and weighing 105 tonnes.
Residents have been told the 'concreteberg' will take at least two months to remove with pneumatic drills and high pressure jets, with work beginning next week.
Tankers will be kept on standby to pump out any backed-up sewage blocked by the concrete, Thames Water said.
The solidified concrete is more dense than a so-called 'fatberg', made up of fat, oil and wet wipes, and has set to the walls of the Victorian-era sewer.
Blockages cost Thames Water, the company that supplies water to London and the Thames Valley, around £18 million each year.
The concrete under Hall Street in Islington alone is expected to cost several hundred thousand pounds to clear.
Alex Saunders, Thames Water operations manager, said: "Normally blockages are caused by fat, oil and wet wipes building up in the sewer, but unfortunately in this case it's rock-hard concrete.
"It's in there and set to the Victorian brickwork, so we need to chip away at it to get it removed.
"This is not the first time damage has been caused by people pouring concrete into our sewers but it's certainly the worst we've seen. It's very frustrating and takes a great amount of time and effort to resolve.
"We're now doing everything we can to deal with it as quickly as possible, making sure our customers don't have to suffer because of this mindless abuse of our network."