What threat do North Korea and Iran pose if they develop full nuclear capability and can the West defuse the tensions?
The immediate security threat from North Korea does not come from the bomb but from the potential for an accident. When the Chernobyl nuclear reactor exploded 20 years ago, the Soviets were able to smother the ensuing fire by dropping concrete on to it from heavy-lift helicopters. But still radioactive fallout reached Cumbria.
North Korea has no means to control such an accident; there are no safety mechanisms in its economy whatsoever. But whether they tested a bomb or not, they have a nuclear energy programme - and they are working with the most dangerous form of nuclear reactor, using fissile material without the high-precision engineering capacity to do so safely.
There are probably minor accidents all the time because they do not have safety equipment or procedures. And there's no early-warning capacity - no one would dare tell the Dear Leader something has gone wrong until there's nothing they can do about it. So there is every possibility a serious accident could happen. The reactor at Yongbyon is 100km north of Pyongyang, a city of several million people, and 280km from Seoul, with 20 million people. It's a dangerous situation. The only thing to do is engage in dialogue with the North Koreans and make some concessions to get the reactor shut down.
In security terms, it's a US problem, though economically, no one wants the sort of disruption such a catastrophe could bring to the region. But in human terms the issue of a potential nuclear accident has to be on the agenda. At the moment, it isn't.
Professor of international relations
The Iranian nuclear programme might be considered an indirect threat to the UK, in terms of affecting British interests in the Middle East. By developing its nuclear technology, Iran shows its superiority and undermines the capabilities of the UK's allies in the region.
Director of the Centre for Iranian Studies, Durham University
Paradoxically, the logic of deterrence, if it is to be believed, would suggest that Iran's acquisition of a nuclear capability may bring greater stability to the Middle East because it would establish a regional counterforce to Israeli nuclear hegemony, and hence Israel would become more circumspect regarding its own military adventurism.
Professor of politics
University of the West of England
The leaders of North Korea and Iran may be extreme, but they have never exhibited signs of suicidal irrationality. Even the US Government does not believe so-called rogue states would be irrational enough to use their nuclear weapons aggressively - they know they would face massive retaliation.
Their primary motivation is defensive: the lesson of recent years is that if you are a dictator you need nuclear weapons to ensure you don't become the object of "regime change"; only rogue states without nuclear weapons get attacked.
Senior lecturer in international politics
Nuclear proliferation coupled with increased global energy needs is perhaps one of the pertinent questions of our time. Perhaps the way forward might be more research into nuclear power sources that do not give rise to weapons-grade plutonium, specifically research into the use of thorium-based reactors.
Reader in nuclear physics
Iran's and North Korea's nuclear programmes may be used by ministers as (spurious) arguments for Trident replacement. I am an abolitionist where nuclear weapons are concerned. A decision to replace Trident would take the UK in completely the wrong direction.
Reader in international relations
London School of Economics
The ability to produce a nuclear bomb has huge symbolic capital. It enables a country to play with the "big boys" - Jthe permanent members of the UN Security Council who have made little effort to dismantle their own capabilities. Just having the potential to build a nuclear weapon gives the impression of state sovereignty and national modernisation, thereby rallying people around the flag and boosting the leadership's authority.
For Iran, it is also an important bargaining chip in its struggle with the US and its attempts to become a regional power. It is essential that the international community works to defuse such tensions. Punishing Iran through sanctions would only encourage it to become more hard line, further destabilising the Middle East. This would be a real threat to UK security.
Lecturer in comparative politics and international relations
University of East Anglia
Iran is striving for regional hegemony in the Middle East, and a nuclear capability will trigger a regional nuclear arms race. With the evident failure of European Union diplomacy, its members must develop a more robust strategy for containing and restraining the growing threat posed by Iran and its proxies, Hezbollah and Hamas.
Head of politics and international relations