The water supplier Thames Water says it has finally found out why Oxford has such a big problem with 'fatbergs'.
When collating the results of a recent survey the firm found that around 80 percent of the city's restaurants were not using fat traps to stop oil and grease spilling into Oxford's sewers. Therefore, the fat collects in the sewer and drains below the city streets and creates the huge, solid deposits, otherwise known as fatbergs.
Earlier this year, a 20 tonne blockage was removed from one drain in the city centre. Kate Bunkall's report explains what happened. The interviewee is Alex Saunders from Thames Water.