The resignation of Gary Cohn, Donald Trump’s top economic adviser, has seen stock markets drop and fears rise that the president is increasing reliant on protectionist advisers.

The Dow Jones fell more than 300 points, around 1 per cent, after Mr Cohn announced he was leaving as the head of the National Economic Council after losing a battle over steel tariffs.

Mr Cohn, a former Goldman Sachs president, was one of the biggest advocates of the free trade in the White House and seen as a curb on Mr Trump’s economic nationalistic instincts.

His resignation means close to half of White House senior staff in place on inauguration day have left their roles - a far higher proportion than other recent presidents.

The White House said on Wednesday that Mr Trump would announce details of his 25 per cent steel tariff and 10 per cent aluminium tariff proposal “at the end of the week”.

It has triggered a fierce backlash from allies such as Britain, Canada and the European Union and leading Republicans like Paul Ryan, the party’s most senior figure in House of Representatives.