Dr Julian Lewis: The intermediate-range nuclear forces treaty of 1987 was based on the zero-option offer, which was a great two-sided ​deal between the Soviet Union and the west. Does the Secretary of State think that there are any lessons to be drawn from the negotiations which led to that successful deal, in that the west faced down the Soviet Union, walked out – or, at least, allowed the Soviet Union to walk out – without a deal when the Russians refused to accept the zero-option offer, and waited for them to come back and do a genuine deal that benefited both sides? Does he think that that successful two-sided deal has any lessons to teach us for the purpose of certain other negotiations that have so far worked out a lot less happily?

[The Secretary of State for Defence (Gavin Williamson): I cannot imagine what my right hon. Friend is referring to, but I think that when it comes to the issue of Russia’s lack of compliance with its treaty obligations, we need to keep hammering home the message, with all our NATO allies, that it cannot ignore its treaty obligations and must start complying with them.]