Excess oil supply is at record-high with three billion barrels on market, says IEA

Saudi Arabia accounts for the largest stock of excess oil in the world

Demand for oil is expected to reach a five-year high in 2015 according to the IEA

The supply of excess oil in the world has reached a record high, it has been reported.

More than three billion barrels of spare oil are floating around on the world market, according to the International Energy Agency (IEA).

The glut is the result of rapid production of oil by the 12 members of the Organisation of Petroleum Exporting Countries (OPEC), and strong production by non-OPEC suppliers.

In its last report, the IEA said this "massive cushion" of excess supply had grown with falling oil prices, which have reached a new normal of about $50 billion barrels a day.

It comes as another report showed the UK alone out of the G7 countries has been increasing subsidies for the fossil fuel industry while cutting support for renewable energy.

Fossil fuel subsisdies were "public enemy number one" to renewable energy industry growth, said the IEA in response to the report from the Overseas Development Institute.

In the IEA's own report on excess oil supply, it said Saudi Arabia accounted for the largest share of the world's excess supply.

The IEA said the excess supply in the world market at large would ensure a steady supply of the fossil fuel.

"Brimming crude oil sticks offer an unprecedented buffer against geopolitical shocks or unexpected supply disruptions," said the report.

Yet it also warned that overreliance on the Middle East as it tried to fight Isis, also known as the Islamic State, could risk unstable conditions.

Low consumer prices has seen energy demand rebound, with the IEA expecting demand to reach a five-year high in 2015.