Arms race | 4 May 2017

Like most documentaries, Britain’s Nuclear Bomb: The Inside Story (BBC4, Wednesday) began by boasting about all the exclusives it would be serving up. Unlike most, it was as good as its word. What followed did indeed contain much previously unseen footage and interviews with people — including ‘this country’s bomb-maker in chief’ — who’ve never before spoken about the part they played in Britain becoming a nuclear power. It also did a neat job of fitting the story to our favoured national myth: the one about old-fashioned British pluck and know-how triumphing over both the odds and the shamefully professional ways of other countries.

In the 1930s, for example, the race was on to split the atom. As a result, the people that the programme, you felt, would really like to have called ‘the Yanks’ (or possibly ‘our gum-chewing cousins from across the pond’) constructed huge machines to produce the millions of volts they thought would be required. Meanwhile in Britain, John Cockcroft worked out that just 300,000 would do the trick — and built a suitably modest piece of kit out of old tea chests to prove it.

At this stage, Britain was duly leading the world. But then came the war and with it Churchill’s generous decision to let America lead the Allies’ charge for an atomic bomb, with our scientists providing only some much-needed back-up. Sadly, his kindness was repaid with ingratitude when the Americans passed the 1946 McMahon Act forbidding the sharing of atomic secrets with the UK — merely because of a (justified) suspicion that some of our guys were Soviet spies.

The question, then, was whether we’d try to create our own bomb; and the answer was, of course, yes. At which point, enter Ken Johnston, the bomb-maker mentioned at the beginning who, given that he was transforming British fortunes in the late 1940s, must be an awful lot older than he looks.