Cycle helmets: promotion or legislation?

Health promotion has been put forward by the Government as the way to achieve a healthy lifestyle. However, this has had mixed success in relation to the reduction of injuries and fatalities amongst pedal cyclists. Many cyclists still do not wear protective headgear, for whatever reason, particularly in the under 15 age group, who are most at risk. Various strategies have been tried to encourage the wearing of head protection, yet this is not 'normal' practice. Should the Government step up the campaign and hope it works or should it legislate in favour of proactive head gear for pedal cyclists as it has for motor cyclists?