It is encouraging we are seriously thinking about desalination to tackle the water shortages in the South-East.

It is rather less encouraging to think, at the same time, we are proposing a sewage outlet for the waste of Brighton and Hove just a few kilometres away.

Sewage contains a great deal more than human waste.

There will be household and industrial waste as well - some of which evaporates at similar temperatures to water.

These materials are notoriously difficult to separate from water and are toxic in very small quantities.

Human waste contains vast numbers of living micro-organisms, some of which are pathogenic.

Many of these are bacteria that can produce highly resistant spores: these spores can be spread in water droplets, and can cause serious infection to humans and other animals.

How do we deal effectively with such micro-organisms? With great difficulty.

We know micro-organisms reproduce at a phenomenal rate.

While we can develop chemicals to tackle them, the microbes can mutate and develop strains which are resistant to these microbicides.

In many parts of the world, the microbes seem to be winning the battle - they are developing resistance to our chemicals faster than we can invent them.

In view of the difficulties in dealing effectively with the pathogenic micro-organisms we already know about, it seems stupid to propose to deliberately pollute the sea with more of them a few kilometres from a desalination plant which will produce water for human consumption.

(a) they and their families are required to drink two litres a day of the water which is produced, and (b) they each sign a form accepting full legal and financial responsibility for any outbreak of disease caused by such a short-sighted venture.

-Dr S Newton, Peacehaven