Unilateralism has something of a bad name, primarily through association with CND and its ilk. Unilateral disarmament flies in the face of all history and experience.
But in other spheres it can be a much more appropriate proposition, and insistence on multi-lateralism can be counter-productive. Two such cases are very topical.
First, environmental measures. Because some types of pollution know no borders, and because clean-up can cost money, it is tempting to say: we all act together or we do nothing. But it is amply evident that (for example) China will do absolutely nothing it does not conceive of as being in its own interest, and will scupper anything that others might seek to impose upon it. However, like any country, it will certainly take whatever measures it sees as being in its own interests which, in the case of the environment, won't at all mean China does nothing.
We should all adopt the same approach: refuse impositions, but take whatever measures we consider right, coordinating with any nation that sees things the same way as we do. If this includes raising tariffs on 'dirty' goods from China, so be it.
Second, a levy on banks. Gordon Brown, forever the coward, has never been willing to address shortcomings in City regulation for fear of 'losing out' to New York or Frankfurt. He attacks Cameron now, for proposing unilateral action to strengthen UK banking structures - and this after the systemic pre-2007 weaknesses have cost us disproportionately. Does he imagine that UK plc can somehow only make its way in the world with an under-capitalised financial sector ? Perhaps under the slogan "Ours is the biggest, so it had better be the weakest" ?
The UK was once synonymous with the highest standards. A British precious-metal hallmark is considered entirely trustworthy the world over: a French hallmark is taken with a large pinch of salt.
We know the cost of racing to the bottom on banking regulation - it is astronomical, and you don't even need a long memory to know it. Do what's right, and let the others catch up. It is its own reward. Go Cameron!