Thames Water wants its Beckton desalination plant back in working order by the end of the year, if needed. It is the only such plant on the British mainland. In 15 years it has run only five times, and its membranes had reached the end of their life. Costs have risen from an initial GBP 270 million to GBP 500 million today.
A reserve plant that rarely runs loses its readiness. Readiness comes from operation, not from construction.
Source: The Guardian