He said: “It’s not the same, but it’s potentially the US’ Brexit moment in many ways.
“And whatever you think of Brexit, it’s going to have a bit of an impact for a bit of a while, across the board.”
US markets shook when the American leader announced his plans to impose 10 per cent and 25 per cent tariffs on all steel and aluminium imports last week.
Mr Janjuah said Donald Trump is only “doing what he said he was going to do in the run-up to being elected”.
He told CNBC: “I think for the US, the world’s core consumer, this isn’t just a US issue. It’s a global issue.
“Mr Trump is kind of doing what he said he was going to do in the run-up to being elected. The market, I think, forgot that.
“But if the market is already concerned about inflation and the Federal Reserve, trade wars, one of the takeaways from that is a bigger risk of inflationary low growth.”
A growing number of world leaders have expressed major concerns about the President’s import tariff plans and fears are continuing to grow about the prospect of a trade war.
The announcement of proposals for a 25 per cent tariff on steel imports and a 10 per cent levy on aluminium prompted a furious reaction from the EU.
The bloc has since drawn up a £2.5billion hit list of retaliatory tariffs.
But Mr Trump said if the EU was to retaliate, he would impose a 25 per cent tax on European cars.
However Mr Trump has attempted to downplay the risks of a trade war saying his tariffs would be applied in a “very loving way”.
He added: “We will straighten it out. We’ll do it in a very loving way. It will be a loving, loving way.
“They’ll like us better and they’ll respect us much more.”
Speaking today, Donald Tusk reacted to Mr Trump’s trade tariffs saying: “Trade wars are bad and easy to lose. It is time for poiliticans on both sides of the Atlantic to act responsibly.”