(DailyMail) -- Mr Corbyn told BBC he would have an 'immediate' security and defence review if he takes power.
When Mr Corbyn was asked if he would ever use nuclear weapons, Mr Corbyn said: 'We want a secure and peaceful world. We achieve that by promoting peace, but also by promoting security. 'Security comes from that process.'
Mr Corbyn was asked what he would write in his 'letters of last resort' to British submarine commanders. The letters dictate what the captains should do in the event of war if they are cut home from London. The Labour leader said he would tell them to do no more than 'follow orders when given'.
Mr Corbyn said he wanted to work with Nato leaders to build a 'sensible relationship' with Russia and added: 'We need to de-escalate tensions around the world'.
Asked about the 800 British troops recently sent to the Nato operation in Estonia, the Labour leader said: 'We would keep those troops there for the moment but we would use the opportunity of a newly elected government to say look we want to reduce tensions.'
And on British air strikes against ISIS in Syria and Iraq, Mr Corbyn said: 'I will say I want to see a process that brings about the end of the conflicts in both of those countries.
'The only solution in Syria is a political one. There is no other way of getting it. There has to be a reconvening quickly of the Geneva peace process.
'In the meantime, no more strikes, have the UN investigation into the war crime of the use of chemical weapons in Syria.'