The two crude oil benchmarks, US West Texas Intermediate (WTI) crude futures and Brent crude futures, both opened the year above $60 (£44.25) a barrel for the first time in four years.

WTI traded flat at around $60.40 by lunch today after hitting $60.74 earlier in the day, the highest since June 2015.

Brent crude futures, the international benchmark, was also flat at around $66.80 after hitting a May 2015 high of $67.29 a barrel earlier in the day.

As violence flares in the Iranian capital, Police have arrested more than 450 protesters in Tehran over the past three days according to the deputy provincial governor.

Protesters also attacked police stations elsewhere in Iran late into the night on Monday, news agency and social media reports said.

One member of the security forces was reported killed yesterday, bringing the death toll to at least 14. The violence is stemming from the boldest challenge to Iran’s clerical leadership since previous unrest in 2009.

Reacting to the disturbances, Ayatollah Ali Khamenei said: “In recent days, enemies of Iran used different tools including cash, weapons, politics and intelligence apparatus to create troubles for the Islamic Republic.”

The protest is the boldest challenge to the clerical leadership since unrest in 2009.

The US-based Schork Report said in a note to clients on Tuesday: “Growing unrest in Iran set the table for a bullish start to 2018.”

Bjarne Schieldrop, chief commodities analyst at SEB, told Reuters: “Geopolitical risks are clearly back on the crude oil agenda after having been absent almost entirely since the oil market ran into a surplus in the second half of 2014."

According to the Iranian government, oil reserves in Iran stand at approximately 150 billion barrels placing it third in the world table with roughly 10 per cent of the world's total proven petroleum reserves.

At 2006 rates of production, Iran's oil reserves would last 98 years if no new oil was found.