Hello, and welcome to NewsHour from the BBC World Service, coming to you live from London.
I'm Paul Henley.
President Trump's swinging global tariffs on goods imported by the US come into effect today.
They've already caught chaos on international markets, with the biggest falls in share prices since the Covid pandemic.
And now they could trigger retaliation and escalating trade wars,
with potentially huge consequences for the global economy.
Let's hear live from Gillian Tett, columnist for the Financial Times newspaper and head of King's College, Cambridge.
Gillian, welcome.
How would you sum up Mr Trump's tariff revolution, and what are the scale of stock market losses?
Well, I think absolutely shocking is the best way to describe it.
He campaigned last year for the presidency on the platform of being the greatest winner ever.
We're going to keep winning, he said.
Most investors will think they've done nothing but lost in the last couple of days.
Do you have tea, that the... I think, Gillian, we're going to have to try and come back to you.
We can't hear all of what you're saying.
The line keeps on cutting out.
Let's talk about one country in the meantime that has really taken the brunt of cuts on its scale.
Some countries face much steeper tariffs than others, under the Trump plan, of course.
And the tiny Southern African nation of Lesotho is a case in point.
It was only last month that Donald Trump referred to Lesotho in disparaging terms