AS DAWN came up over New Mexico on 16 July 1945, a scientist named Otto Frisch saw the nearby hills "bathed in brilliant light, as if somebody had turned the sun on with a switch". Frisch turned to face the source of the light, recalling later that "it now looked like a pretty perfect red ball, about as big as the sun, and connected to the ground by a short grey stem". What he had just witnessed was the detonation of the world's first atom bomb. Another observer, the American scientist Robert Oppenheimer, realised the significance of what he had seen and recalled a line from the Bhagavad-Gita: "I am become death, the shatterer of worlds".

Oppenheimer's invocation of the Hindu epic was symbolic, an acknowledgement of the way in which technology, far from representing progress, threatened to bring about destruction on a scale hitherto confined to legends. In the last month, thanks to a right-wing nationalist government in India, the Hindu bomb has become a reality. This event, unthinkable in 1945, has been followed swiftly by nuclear tests in Pakistan which have been crudely characterised as the first Muslim bomb, and what difficulties the West finds itself in as a result. The United States has imposed economic sanctions on Pakistan, as it has already done on India. Britain has not yet followed suit, partly because its aid programme is targeted on the poorest sections of the population whose situation can become only more dire as money is sucked into the development of ruinously expensive nuclear weapons.

We are left with public remonstrances from world leaders. On Tuesday, Tony Blair telephoned the Pakistani prime minister, Nawaz Sharif, and warned that nuclear weapons are not the way to achieve international recognition. I am not an admirer of Mr Sharif, but I hope he laughed long and hard in response. How else, he might have asked, does a nation qualify for a permanent place on the UN Security Council? Are Britain, China, France, the US and Russia there because they are mature democracies to whom the rest of the world gladly defers? Am I Father Christmas?

Mr Cook was equally fatuous, announcing on Radio 4's Today programme that Pakistan's security had not been enhanced by the tests. Excuse me? Isn't that why Britain and the US insisted on building up huge nuclear arsenals during the Cold War, arguing that the West's security depended on the Soviet Union's awareness that any nuclear strike would be met with equal force? We even had a word for it, deterrence, and it's hard to see why it applies in one context and not another. Mr Cook's party is as keen to hang on to nuclear weapons as the Conservatives: it was a post-war Labour government, headed by Attlee, which started Britain on this road in the first place.

When a leading scientist, Professor Patrick Blackett, suggested Britain should stay out of the nuclear race, he was given short shrift by the then foreign secretary, Ernie Bevin. Mr Attlee's own stand on Britain's top-secret nuclear weapons programme would doubtless appeal to the current leaders of India and Pakistan: "For a power of our size and with our responsibilities to turn its back on the bomb did not make sense." Perhaps Mr Cook could explain why it is fine for Britain to stick to this policy, but not for the developing world to follow our example? As someone who has supported unilateral nuclear disarmament throughout my adult life, I have only one more thing to say on the subject: I told you so.

THE Downing Street press office had other things on its mind last week, dropping its own bombshell on the subject of gender relations. As the rest of us worried about the arms race, a spokesman issued a statement about Cherie Blair's exercise regime. Denying reports that Mrs Blair had lost two stones, the spokesman insisted: "She's the same weight as she was during the election campaign. She lost weight before the election after a quite deliberate disciplinarian regime". At this point, I advise sensitive readers to brace themselves. "Mrs Blair has maintained the regime ever since," this spokesman went on, "so she can continue to be a credit to the prime minister."

I just hope all those commentators who wrote drooling profiles of Mr and Mrs Blair immediately after the election feel suitably ashamed of themselves. Far from being a model to us all, a working parent who shares with her husband the responsibilities of family life, it transpires that Mrs Blair is that old-fashioned species, a trophy wife. And one who, according to accounts of her sessions with a private trainer and of her low-fat diet, has to work hard at it.

I cannot imagine that such a major policy switch applies only to Mrs Blair. What about all those women MPs and councillors, some of them a little heavier round the middle than they used to be? Clearly what is needed is a New Labour fitness video, fronted by Cherie in a nice leotard and available by post to all party members of the - how shall I put it? - feminine persuasion. Lose Weight for the Leader! Tone up for Tony! If I were Rosemary Conley, I would be seriously worried.

POOR old Cher, meanwhile, has worked out and undergone plastic surgery, and at 52 she's miserable. In particular, she's worried that it's no longer so easy to attract men: "I live in Los Angeles where newer is better and older is useless". Her remarks echo the conclusion of Elizabeth Wurtzel's new book, Bitch, in which she produces this dolorous observation about growing older without a man: "Remaining single is not really a choice, it's a sentence".

These lucubrations strike me as ridiculously old-fashioned. They are also based on a failure to grasp a striking feature of the way we live now, which is its fluidity. "Married" and "single" no longer mean what they used to, inflexible states which could be altered only with tremendous effort - a genuine life sentence. Like most of my friends, I have been married, single and somewhere in between, and I expect the pattern to go on repeating itelf. When I explained this theory to Elizabeth Wurtzel just before we appeared on Woman's Hour, she cheered up immediately. Now I'm wondering how to get the message to Cher. I can't bear to think of her exercising away, a New Labour babe in the making.