Thames Water say a lump of fat the size of a double-decker bus has been discovered and removed from a London sewer.
The 'fatberg' of food fat mixed with wet wipes formed in drains under London Road in Kingston.
Gordon Hailwood, waste contracts supervisor for Thames Water said:
"While we've removed greater volumes of fat from under central London in the past, we've never seen a single, congealed lump of lard this big clogging our sewers before.
"Given we've got the biggest sewers and this is the biggest fatberg we've encountered, we reckon it has to be the biggest such berg in British history... If we hadn't discovered it in time, raw sewage could have started spurting out of manholes across the whole of Kingston"
More top news
Reclaim the Power stage a protest at Heathrow against a new runway or further airport expansion.
Eight more people were hurt in the collision.
Police are hunting a man who is suspected of grabbing an 11-year-old girl who only got away by biting her attacker's hand.