Dr Julian Lewis: While the signing of treaties of this sort can lead to political advance, does my right hon. Friend agree that the history of the biological weapons convention of 1972, which ​was exposed in 1992 as having been broken from day one for 20 years by the then Soviet Union, shows that in reality our security depends on the twin pillars of the independent strategic nuclear deterrent and our alliance, through NATO, with the United States of America?

[The Secretary of State for Foreign and Commonwealth Affairs (Boris Johnson): My right hon. Friend is absolutely right. I would also say that the JCPOA (Joint Comprehensive Plan of Action, i.e. Iran Nuclear Deal) has depended not on trust – not on believing the Iranians – but on independent verification, which has been carried out countless times.]