Tomorrow a public inquiry will begin in Suffolk to decide whether or not we in Britain build an American-designed nuclear power station.

"Horizon" asks: are we going to build the wrong reactor, for the wrong reasons, at the wrong time? Despite the fact that a similar type of reactor destroyed itself at Three Mile Island in 1979, our Central Electricity Generating Board argues that we are buying tried and tested technology.

But "Horizon" discovers that a continuing series of design changes have priced it out of the market in America; that no American electrical utility has ordered a PWR since 1978; that many American designers have been dogged for years by an Achilles' heel which affects its safety and economics; and that our neighbours the French are getting cold feet over the scale of their national nuclear programme, based on a similar reactor.

Meanwhile, the most dependable reactor in the world - from Canada - has been totally ignored.