[10] Architects Broadway Malyan designed the plan to RIBA Stage D and acted as expert witness at public enquiry.

[11] The plant was planned to supply 150 million litres of water a day which caters for 400,000 households or 900,000 people in the high-demand seasons when it is most-run.

Its supply is pumped to north-east London in an 8-mile (13 km) pipe which can hold 14 million litres of water, of 1.2 metre diameter.

[12] In 2022, Thames Water revised the usable output of the plant down to 100 megalitres per day, because of "unrealistic expectations" in the design.

Mineral salts, as found in the company's conventional water sources, are added before final purification.

[7][16] Labelled a "white elephant" by MPs, Beckton has operated just three times since it opened and can only supply two-thirds of its planned 150m litres a day.

[17] London Mayor Ken Livingstone criticised the plant in 2007, calling it a "misguided and a retrograde step in UK environmental policy."