Peter Fookes writes In October, 2005 my wife and I enjoyed the 21st anniversary celebrations of the Thames Barrier in London, and spent an excellent day on-site enjoying the presentations, lunch and an extensive tour of the Barrier. A delightful keynote speech was given by the actor David Suchet (Chairman of River Thames Alliance, also well known as Hercule Poirot in the TV series). Following the main engineering presentation, Baroness Barbara Young (Chief Executive of the Environment Agency, who was host for the day) gave the closing address. The Thames Barrier (Fig. 1) was, and is, needed because it was said at the time of the design that the increasing volume of the world's oceans, plus a possible sinking of south-east England meant that the relative level of the Thames was rising at about 300 mm per century. Hence floods were becoming more severe. As a result, the defences of London (with some 1.25 million people and 80 billion pounds of property at flood risk) comprise some 295 km of floodwalls and embankments, with nine tidal barriers - including the Thames Barrier - as well as 3 5 gates and over 400 minor floodgates. Most of these works were designed in the 1970s, basically as a response to the devastating East Coast floods of 1953, when more than 300 people died in Britain (sadly, the same event killed many more in Holland). To date the Barrier has been successfully raised in anger over 80 times since 1983.
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