Fighting fatbergs: 'This is now a huge environmental issue'

Christmas is peak time for blockages and consumers are urged to be more careful about what they put down pipes

It looks like a 5ft-long grey sausage made of hundreds of scruffy pieces of fabric. On closer inspection, brightly coloured plastic, condoms and rubber bands can be identified in the bizarre-looking mass.

This is known in the water industry as "rag", the technical term for items that do not degrade once they have been flushed down the toilet. The greyish material that dominates the mass is wet wipes, now the scourge of the UK's sewers. Combined with fat and grease that has been tipped down sinks, it is already starting to build up into a fatberg.