As Rory Medcalf said yesterday, often the most memorable things to come out of big events like the Shangri-La Dialogue are from the working groups rather than the big set-piece speeches.

That was true not only of Rory's session on incidents at sea, but the one I attended yesterday on ballistic missile defence. On its face, a dry topic, but we're actually talking about defensive systems that can protect countries from nuclear annihilation, and as a result what we witnessed was a genuine and sometimes passionate strategic and political debate.

The stars were Russian Deputy Defence Minister Anatoly Antonov, Major General Michael Keltz from US Pacific Command and Chinese Major General Yao Yunzhu. Keltz raised eyebrows early on when, in the course of making the case that US missile defences against North Korea were a stabilising force, he made an analogy with the Middle East, saying that Russia's sale of S-300 missiles to Syria was actually a stabilising move.

When questioned whether this meant that the Keltz also thought the Russian sale of such missiles to Iran and North Korea would also be stabilising, Keltz said the logic only applied to 'rational actors'.

Keltz was animated in his response to General Yao's concern that US missile defences could be threat to China's nuclear deterrent, given that these defences could 'mop up' remaining Chinese missiles after a disarming first strike. Keltz said nuclear war between China and the US was unthinkable and that any talk of a first strike was 'baloney' and 'a farce'. Yao responded by asking why the US did not therefore make a no-first-use pledge.

In regard to US missile defences in Europe, which are designed to take down Iranian missiles, Russia's deputy defence minister asked drily why the Administration did not trust its own CIA, which assesses that Iran has no missiles that could reach the US. It was also interesting to hear Antonov say that Russia had no problem with South Korea's tactical missile defences, though he drew the line at 'strategic' missile defence.

The discussion actually got quite heated whenever North Korea came up, with General Yao asking, 'Don't you think they feel threatened? Is their security situation favourable?'

I can't finish without mentioning South Korea's Dr Chung Min Lee from Yonsei University, who was also on the panel and directed some very blunt comments towards China, asking what Beijing would do if a bordering country, with unprovoked aggression, sank a Chinese naval vessel and shelled an island military installation. Would China not find ways to defend itself?

Then, after an intervention from a Pakistani delegate who had questioned South Korean policy, Chung Min Lee passionately denounced Pakistan's proliferation record, saying that the AQ Khan network had bequethed the world one of its biggest security problems.

Photo by Flickr user Ted Lipien.