A leading British think tank said on Wednesday that the country's already slow economic growth rate could be more than halved if Donald Trump wins the U.S. presidential election and imposes sweeping import tariffs. In its latest report, the National Institute of Economic and Social Research painted a bleak picture for Britain's economy over the coming years - even without Trump's tariff plan - with growth seen slowing to 1.1% in 2026 from 1.2% next year and only reaching a lacklustre 1.7% in 2030.