A 64-meter-long mass of hardened fat, cooking oil and wet-wipes is posing a challenge in a town in southwest England.

Dubbed a "fatberg" by local officials, the mass is said to be the biggest ever discovered in Devon or Cornwall. It is roughly the length of six double-decker buses, and it originated with waste disposed of in drains in the town of Sidmouth.

South West Water’s Director of Wastewater, Andrew Roantree, said in a statement, “It shows how this key environmental issue is not just facing the UK’s cities" but in coastal towns as well.

Roantree said it would take workers around eight weeks to clean the clog in what he described as "exceptionally challenging work conditions."

A fatberg forms like a snowball. As wet-wipes get flushed down loos, fats, oil and grease congeal together, gradually forming a hard mass known as a fatberg. Removal is due to start in early February, but heavy rain that time of year could cause delays.

Sewer workers will require full breathing apparatus to carry out the removal, which will involve a combination of manual labor and sewer jetting equipment.

South West Water's sewer network is around 17,000 km in length. Crews tackle a new sewer blockage at a rate of one an hour.