Saudi Arabia faces a vicious liquidity squeeze as capital continues to leak out the country, with a sharp contraction of the money supply and mounting stress in the banking system.

Three-month interbank offered rates in Riyadh have suddenly begun to spiral upwards, reaching the highest since the Lehman crisis in 2008.

Reports that the Saudi government is to pay contractors with tradable IOUs show how acute the situation is becoming. The debt-crippled bin Laden group is laying off 50,000 construction workers as austerity bites in earnest.

Societe Generale’s currency team has advised clients to short the Saudi riyal, betting that the country will be forced to ditch its long-standing dollar peg, a move that could set off a cut-throat battle for global share in the oil markets.

Francisco Blanch, from Bank of America, said a rupture of the peg is this year’s number one “black swan event” and would cause oil prices to collapse to $25 a barrel. Saudi Arabia’s foreign reserves are still falling by $10bn (£6.9bn) a month, despite a switch to bond sales and syndicated loans to help plug the huge budget deficit.