Here's some text from their manifesto-
Gun Control and Gun Crime
CJ500 Gun crime is a particularly serious problem and the Green Party is committed to tackling it by ensuring a high level of gun control as well as addressing the social factors which contribute to people committing crimes with guns.
Also, as well as their actual use, the presence and availability of guns and 'gun culture' contributes to fear of crime, intimidation and the reluctance of witnesses and victims to report crimes.
The Green Party is committed to introducing the following measures:
Defining lethal weapons
The lethality of a gun will be defined quantitatively in law, thereby covering new weapons resulting from developments in firearms technology.
The most dangerous weapons will be prohibited. These include handguns, multi-shot and high calibre weapons. There will be a complete ban on the private ownership/possession of all automatic and semi-automatic firearms. A suitably constituted Gun Safety Advisory Committee will regularly review which weapons are prohibited.
All deactivated weapons will be treated the same as active weapons in terms of prohibition and licensing, as they are capable of being reactivated and can cause fear because they appear as though active.
A single rigorous licensing process will be put in place based on considerations of public safety rather than the convenience of shooters. Subject to relevant criteria, licenses will be issued for permitted shotguns and rifles, all lethal airguns and permitted deactivated guns.
Users of firearms for sporting or agricultural purposes will be required to demonstrate their competence in handling firearms and satisfy the authorities of their mental and emotional stability:
Applicants should also be required to obtain the signature of, say, ten citizens (just as a prospective electoral candidate) who will vouch for the good character of the licence holder. This will discourage the 'loners' and socially isolated individuals who are most at risk of committing the horror that occurred at Dunblane and Hungerford.
The cost of medical and psychological tests must be borne by the applicant, together with a new annual fee which is sufficient to repay the economic damage - to police, court and NHS - inflicted on it by the abuse of guns generally. When licences are awarded the onus will be on the applicant to demonstrate his or her suitability to handle firearms rather than on the authorities to prove the applicant's unsuitability. Licence holders will be required to renew their applications on an annual basis individuals whose licence application is rejected will be required to wait at least two years before re-applying.
There will be a complete ban on the manufacture, sale and import of imitation weapons (replica guns and blank firers) and a ban on their public possession. There will be licenses for imitation weapons used for film/theatrical purposes, and legislation to ensure toy guns are highly distinct in appearance, probably by being made of clear/translucent plastic.