A US tariff of 10% on UK goods could cost the Northern Ireland economy £85m and 800 jobs over the next 15 years, a Department for the Economy study has suggested.

It does not mean the economy will shrink in absolute terms, rather it will be smaller than it would have been if the tariffs had not been imposed.

The study only considers the direct effects on Northern Ireland exports rather than any secondary effects.

The impact would rise to a £110m loss of potential economic output if US President Donald Trump was to impose a 20% tariff on pharmaceuticals.

Pharmaceuticals is the part of the Northern Ireland economy which is most exposed to Trump tariffs as almost half of the sector’s export sales go to the US.

The study suggests a 20% tariff would mean pharmaceutical sector output would be around 5% lower compared to a no tariff scenario.

Tariffs are effectively a tax on imported goods and are a major part of Trump’s economic policy.

Since re-entering office in January, he has raised tariffs on specific items such as steel, aluminium, and cars and imposed a blanket 10% levy on most goods from trading partners around the world.

He had briefly targeted some countries’ exports with even higher tariff rates, only to suspend those measures for 90 days to allow for talks.

A US trade court has ruled that an emergency law invoked by Trump did not give him the unilateral authority to impose the blanket 10% tariffs.

However, those tariffs are still being collected while the Trump administration appeals the ruling.

The administration is also conducting a national security investigation into pharmaceutical imports, a process which would provide a more solid legal basis to impose tariffs on that sector.

The study concludes that tariffs will “adversely affect local businesses and represent a significant headwind for businesses when trying to grow exports over the longer term”.

“It is also likely that many of the businesses impacted will be in specific geographic areas e.g. Mid Ulster and Armagh, Banbridge and Craigavon council areas,” it says.

“This is due to the importance of the manufacturing and pharmaceutical industries to these areas, which will have implications for the regional balance agenda being taken forward by the department.”