Sewer workers investigating the 'berg say that over time it has solidified, and is now as hard to remove as concrete.
The capital's largest ever recorded fatberg, weighing in at 15 tonnes, was found in Kingston in August 2013. The crews are removing 20 to 30 tonnes a day, working 8am to 5pm, seven days a week, removing the matter for disposal at a recycling site in Stratford.
In a sewer region located about 11 feet (4 meters) under the Whitechapel neighborhood in London, workers are just beginning to dismantle an inanimate but uniquely revolting inhabitant - a vast and rock-solid plug of oily waste charmingly known as a "fatberg".
Getting rid of the fatberg will require eight workers to use high-pressure hoses to break it up.
Thames Water engineers have said it will take them three-weeks to clear the mass. "It's frustrating as these situations are totally avoidable. the sewers are not an abyss for household rubbish".
CCTV camera inspections revealed the 1200mm-high by 700mm-wide sewer was totally blocked by the fatberg, which is 3.5 meters below ground.
Thames Water says it spends about £1m a month clearing blockages from sewers, which can help contribute to flooding.
Rimmer said: "When it comes to preventing fatbergs, everyone has a role to play". That's an average of three fat related blockages and 4.8 blockages caused by items like wet wipes every hour. Water company officials call it a fatberg.
The utility has introduced a "Bin it - Don't Block It" campaign to discourage its customers from flushing problematic items down the toilet. It also visited food outlets earlier this year to discuss how they dispose of fat and food waste.