Trade wars: what are they good for?

Donald Trump stands accused of firing the starting pistol on an international trade war after pressing ahead with his threat to slap tariffs on EU steel imports.

Here we look at what it all means.

Trade wars, what are they good for?

The US steel industry, Mr Trump hopes.

Tariffs on imports should trigger increased demand for US steel, which will be welcomed in the Midwest 'rust belt', where Mr Trump got a lot of support at the 2016 election.

However, US steel consumers would have less choice and could be forced to pay more for steel products, which could mean higher prices.

What will tariffs mean for the UK?

Around 7% of the UK's steel output, 350,000 tonnes, was exported to the US in 2017. So the industry fears the tariffs could cause serious damage.

How big is the UK steel industry?

It is still a big employer despite shrinking considerably in recent decades.

Around 4,000 people are employed at Tata's giant Port Talbot steelworks in south Wales. British Steel, which in its current form was founded in 2016 from assets acquired from Tata by Greybull Capital, has production sites in Scunthorpe, Skinningrove and Teesside.

How important is the UK steel industry?

It accounts for less than 1% of economic output. But it is still regarded as strategically important for both manufacturing and defence.

UK steel was used to build the Queen Elizabeth aircraft carrier. It is also used extensively by UK car manufacturers.

What happens next?

Unless Mr Trump backs down, a trade war seems inevitable.

The EU has already prepared a list of US imports for retaliatory tariffs, including bourbon, blue jeans and Harley-Davidson motorbikes.

And like military wars, trade wars have a tendency to escalate.

So what?

Tariffs on imports generally mean higher prices for consumers.

And according to most economists, trade wars are not usually good news for overall global prosperity.