Global markets shook at the prospect of a new era of protectionist trade policies after Donald Trump was elected US President. The Republican candidate won key swing states – such as Florida, Ohio and North Carolina – which cleared the way for his Brexit-style upset.

Futures contract - judgements on the direction of travel before the markets open in America - point to the Dow Jones Industrial Average plunging by 800 points when it opens later today (9 November).

Trump has vowed to cut taxes, deport around 11 million illegal immigrants and rip up existing trade agreements, such as the North American Free Trade Agreement.

Economists at the US-based think tank Macroeconomic Advisers estimate his policies could set the US back $2.1tn over the next five years.

Nigel Green, founder of financial services consultant deVere, said: "Buckle up for a bumpy ride in the global markets.

"Whether President Trump will, in fact, do what he has said he will do throughout his campaign, or whether it was just soaring rhetoric to whip up his support base, for now, Trump winning is sending shockwaves across the world. As such, enormous volatility can be expected in the markets."

Overnight as a win for Trump looked increasingly likely, Asian markets were the first to fall. Tokyo's Nikkei 225 Index was 5.4% down, Hong Kong's Hang Seng slipped 2.5%, while Sydney's ASX All Ords was 2% lower.

In Europe, the FTSE 100 Index opened 102.8 points down, or 1.5%, to 6740, knocking more than £25bn off the value of blue chip shares. Germany's DAX was up slightly, but the Cac 40 in France plunged by 2.7%.

The US dollar was down against a basket of world currencies. The pound was up 0.3% against the dollar at 1.241. The dollar was also lower against the euro and the Japanese yen.

Japan''s central bank holds crisis talks

Japan's government and its central bank will hold crisis talks today as traders flood into its currency, viewed as a safe haven, sending its value higher.

But the Mexican peso plunged by more than 13% against the dollar, an all-time low at less than 20 pesos to the greenback. Trump has pledged to build a wall against its southern neighbour, and deport millions of illegal immigrants back to Mexico.

Mexico's central bank also said it will hold a joint news conference with the finance ministry later today to outline how it will respond to the currency's devaluation.

Gold, another safe haven for investors in uncertain times, jumped as much as 5% to $1,337.40 an ounce.

Eric LonerganMacro fund manager at M&G Investments said: "The critical unknown is whether a Trump presidency pursues the policies of Trump the candidate, in particular his anti-trade, anti-China and anti-Mexico policies. But the real concern is that he will do what he says."

US election night 2016
Republican president-elect Donald Trump along with his campaign manager Kellyanne Conway acknowledge the crowd during his election night event at the New York Hilton Midtown in the early morning hours in New York City Mark Wilson/ Getty Images