The draft was leaked to newspapers - a sign of the divisions that have deepened in the party under Mr Corbyn, whose backers have driven the move leftwards against the wishes of many MPs.
Despite being the least active of all the party leaders on social media, Mrs May's posts have been shared or liked roughly twice as often as Mr Corbyn's on Facebook, on average. In front of dozens of journalists and camera crews, Len McCluskey, the general secretary of Unite, appeared to fall backwards down the stairs. "And pandering to an erratic Trump administration will not deliver stability".
"It doesn't make me a pacifist". To this end, most Labour MPs avoid direct criticism of the leader, although voters don't hold back in blaming him for the party's poor standing.
May's Conservatives see Corbyn's opposition to military action and nuclear weapons as a major weakness to be exploited in campaigning for the June 8 election.
Jeremy Corbyn anticipates the pledges in Labour's manifesto - a draft of which was leaked on Wednesday - will be "very popular".
A draft of Labour's manifesto leaked on Wednesday night said the party would place "peace, universal rights and global law" at the heart of foreign policy, while committing to meeting the North Atlantic Treaty Organisation target of spending 2% of GDP on defence and to maintaining the Trident nuclear deterrent.
The Conservatives sought to rubbish the Labour leader's speech with Boris Johnson saying Mr Corbyn was "a guy who has campaigned all his life to weaken the UK's defences". Corbyn said that he realized that military action may be necessary "as a last resort", but vowed to focus on defusing tensions.
Though never brought into being under Tony Blair, Cook's idea was for a foreign policy based on human rights, the rule of law, and trade.
Having faced criticism for being unclear of his position on Britain's divorce from the European Union, Corbyn said the issue of whether Brexit should happen had been settled, and went on to set out his negotiating objectives.
"The fact is that the "war on terror" which has driven these interventions has failed", he said.
He was later asked whether, as Prime Minister, he would back the like-for-like replacement of the weapon system.
In an effort to bridge party divides over Trident, the manifesto commits Labour to the nuclear deterrent. "In fact, many would say, just the opposite", he said.
He said: "If circumstances arose where that was a real option, it would represent complete and cataclysmic failure".