The FTSE 100 Index retreated from record highs notched up on Monday to drop more than 60 points at one stage after opening, later standing around 0.5% down at 8823.
Falls were also seen across Europe, with the Dax in Germany sinking 1.7%, while the Cac 40 in France was 1% down.
After initially pausing the tariffs, Mr Trump said that starting just past midnight local time, imports from Canada and Mexico would now be taxed at 25%, with Canadian energy products receiving 10% tariffs.
In addition, the 10% tariff that Mr Trump placed on Chinese imports in February is doubling to 20%.
The move – which was followed swiftly by retaliatory action from Canada and China – sent US …