A solidified mass of wet wipes, nappies, fat and oil weighing an estimated 130 tonnes is blocking a 250-metre length of Whitechapel sewers in East London, threatening an obnoxious eruption.

Thames Water said it is likely to take three weeks to dissolve the outsize fatberg.

They caution against expecting quick results as the fatberg weighs as much as 11 double-decker busses.

Thames Water’s head of waste networks Matt Rimmer said: “This fatberg is up there with the biggest we’ve ever seen. It’s a total monster and taking a lot of manpower and machinery to remove as it’s set hard.

“It’s basically like trying to break up concrete. It’s frustrating as these situations are totally avoidable and caused by fat, oil and grease being washed down sinks and wipes flushed down the loo.”

Eight workers are using high powered jet hoses to break up the blob before sucking it out into tankers for disposal at a recycling site.