For quite a long time European Union, with UK, France and Germany as active negotiators, has tried to get Iran to follow the rules of the Non-proliferation Treaty it has signed. Instead they have secretly developed nuclear capacity and a new range of missiles capable of reaching Israel as well as parts of Europe. The old policy has failed.
In the link enclosed you can find the British newspaper The Guardian reporting on how Iran is trying to buy modern nuclear knowledge and technology as well as missile-technology.
Only by Europe and US uniting on a common policy there will be achievements with this regime of extremists.