CCTV investigations in London Road, Kingston found a mound of fat the size of a bus had reduced the 70 x 48cm sewer to just 5% of its normal capacity.
Thames Water has begun repairs to 20 metres of the damaged pipe and work is expected to take up to six weeks to complete.
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Scotland Yard confirm that two people arrested in connection with the attack on Westminster have been released with no further action
An appeal to support the family of murdered policeman Keith Palmer has reached more than £700,000 in two days.
PC Keith Palmer will be remembered permanently at the National Memorial Arboretum, Home Secretary Amber Rudd has said.