In early afternoon trading, the price of West Texas Intermediate oil was $138.95 a barrel on the New York Mercantile Exchange, a gain of almost $6 on the previous week, and around $1 shy of the all-time record of $139.89 set on 17 June.

Opec’s president Chakib Khelil says oil prices could rise to between $150 and $170 a barrel during the summer although he does not think it will hit $200 a barrel.

Libya’s National Oil Corporation chairman, Shokri Ghanem, has also warned that it may make reductions due to the ongoing threat of sanctions against Iran and US legislation allowing lawsuits against Opec.

The market has been unmoved by Saudi Arabia’s meeting in Jeddah on 22 June which aimed to find a solution to record oil prices and investigate the role of speculators in financial markets.

While Saudi Arabia pledged to produce an extra 200,000 barrels a day and to expand its output capacity in future years if needed, few other measures were agreed at the meeting between high profile consumers and producers.