Britain first decided to secure a full-scale independent nuclear weapons capacity in the 1950s and then opted to replace and upgrade what it possessed in the 1980s. In both cases, the policy was extremely controversial. In the 1950s, huge numbers of people marched to “ban the Bomb” and the issue ripped the Labour Party apart, pitting the bulk of its activists and members against the leadership. In the 1980s, the matter was more fraught, with hundreds of thousands of people taking part in demonstrations and Labour committing itself to unilateral nuclear disarmament, a stance that as much as anything else led to the formation of the SDP and formal schism. It was only as the Opposition changed its mind here under Neil Kinnock (who has had a few changes of mind on this question) that it began to resemble a credible party of government.

Compared with the bitter divisions of the past, the debate and vote in the House of Commons yesterday was relatively mundane. No member of the Cabinet has even considered resignation. Margaret Beckett, a passionate unilateralist two decades ago, endorsed a successor to Trident and was joined in the Ayes lobby by Peter Hain, a member of CND until very recently, and Hilary Benn, whose father remains adamantly hostile to Britain’s nuclear status. A few lowly ministerial figures left their posts, although they can expect to be offered a return by Gordon Brown. Although more than 90 Labour MPs rebelled, their “revolt” may prove inconsequential. Even the amendment set down by the Labour Left referred to “delaying” this vote, not abandoning nuclear weapons. Public protest was largely confined to a pair of hardy souls who commandeered a crane in the vicinity of Parliament.

That endorsing a replacement to Trident has not sparked intense discussion does not mean that this has been an insignificant exercise. Debate was muted because the outcome of the Cold War showed that the multilateralists rather than the unilateralists were right. Political circumstances are different today, but the assertion that a British independent nuclear deterrent only ever made sense in the context of a threat from the Soviet Union is very hard to sustain. Furthermore, many on the Labour soft Left have seen the logic of the argument that if Britain is to be an important enough member of the international community to be a major force for good in places such as Africa, then it also has to be a nation that shoulders its full international military responsibilities.

A large part of this is the maintenance of global order, including being part of a network of deterrents against rogue states and rogue groups that themselves may be determined to obtain weapons. It would be a bizarre response to the emergence of the likes of Iran, especially, and North Korea as aspiring nuclear nations to claim either that they would be less likely to acquire an atomic arsenal if Britain opted out of this theatre or that the world would be a safer place with a nuclear capacity in their hands, but not in Britain’s. It would be equally strange to contend that the checks and balances that might be necessary to keep a possible nuclear arms race in the Middle East within acceptable limits would be assisted by Britain downgrading its military standing.

It will be 50 years this October since Aneurin Bevan, the hero of the Labour Left, assailed a motion backing unilateral nuclear disarmament at the party conference with the fiery phrase: “You call that statesmanship? I call it an emotional spasm.” Half a century on, his words still ring true.