The Labour leader has been a lifelong opponent of military intervention overseas.
Unsurprisingly, the Tories say that it all shows Mr Corbyn can not be trusted with the nation's defences - accusing him of undermining Trident and dithering over IS while tying the hands of Britain's intelligence services.
In a keynote speech on defence and security at the Chatham House think tank, Corbyn stressed that his "first duty" would be to protect Britain by using diplomacy and defusing tensions around the world.
Mr Corbyn however said the Prime Minister's leadership approach was risking more deaths in Syria and Labour would take a completely different approach to global affairs accusing Ms May of "pandering" to Donald Trump in the White House.
Emblazoned with the phrases "Theresa May: For Britain" and "Strong, stable leadership in the National Interest", the blue bus is touring round the North East for the rest of the day.
"He says he wants to change Britain - and that's true", said Mrs May.
Referring to the widely publishing photograph of Trump holding May's hand in the White House during her visit in January, Corbyn said: "Britain deserves better than simply outsourcing our country's security and prosperity to the whims of the Trump White House".
Polish left-wing groups have called on Poles in the United Kingdom to support the Labour Party in the upcoming British parliamentary election, a statement by the Polish branch of Labour International has said.
"What this country needs is a strong, clear and robust approach to our defences and I am afraid Jeremy Corbyn's approach is chaotic and offers the reverse". "I will be doing everything I can to earn their trust". "They have not increased our security at home - rather the opposite - and they have caused destabilisation and devastation overseas".
The document, believed to have been signed off by Labour's shadow cabinet during a meeting yesterday afternoon, paints a picture of an energy market wholly different from its current guise, with large swathes of it brought under government control. Over and over again they say he is "not a leader".
"It would mean five more years of putting the few before the many; of the NHS being run into the ground; of extreme cuts to our public services; of young people being let down".
Instead, Corbyn would create a "Minister for Peace" who would guard against this instinct to "bomb first".
He sought to ease concerns he was soft on defence by adding: "I am not a pacifist".