The Libyan regime of Muammer Gaddafi must be stopped from killing its own people. No-fly zones are one option, but carry considerable risks. They imply a major attack on Libyan air defences, causing casualties. Colonel Gaddafi would depict this as an act of war, with highly uncertain political consequences. But even without removing the military option, there are non-violent measures that can and should be implemented now.

As a British diplomat I worked on sanctions and no-fly zones in Iraq and Libya. Both episodes offer lessons about what works, and stress the crucial importance of avoiding harm to civilians. A push on non-violent measures, therefore, could make real progress in Libya, and set a positive precedent to assist those fighting dictatorship elsewhere.

First: boycott. The assets freeze and travel ban imposed by the recent UN Security Council resolution are welcome, but they are clearly not doing enough to stop Col Gaddafi. International Criminal Court investigations will also take time, given that the court has not won a conviction in a decade of operation. Instead, governments should now prohibit all payments to the Libyan government, and its many quasi-state entities. This would mean formal economic sanctions, if hopefully only as a short-term measure.