Sir Keir also called for the UN to be reformed and strengthened, saying the war in Ukraine was a test for the organisation.
He said the UK would “stand with Ukraine for as long as it takes”.
“Because the alternative would be to confirm the worst claims about this place.
“That international law is merely a paper tiger and that aggressors can do what they will.
“We will never let that happen.”
Sir Keir’s speech was intended to show that under his premiership, the UK would offer “responsible global leadership”.
He announced a new British International Investment initiative, working with the City of London to use billions of pounds from pension and insurance funds “to invest in boosting development and fighting climate change”.
Sir Keir also called for a new international levy on global shipping to “put a price on the true cost of emissions” with the money raised going to tackle climate change.
Meanwhile, he demanded changes to the UN Security Council “to become a more representative body” which was “willing to act – not paralysed by politics”.
That would involve permanent African representation on the body,
The existing five permanent members – the UK, US, France, China and Russia – should be joined by Brazil, India, Japan and Germany, he said.
And Sir Keir promised a change in the way the UK acted too: “Moving from the paternalism of the past towards partnership for the future.
“Listening a lot more – speaking a bit less.”
