Oil hits record at $108 a barrel
The cost of petrol in the US and UK is soaring
The price of crude oil has hit an all-time high for the fifth time in six trading sessions. New York sweet light crude touched a new high of $108.21 a barrel, before edging down to trade at $107.93.
Analysts say traders are investing in commodities to protect themselves against the falling dollar.
Another factor pushing up prices is last week's decision by producers' cartel Opec to keep output unchanged, despite rising demand in China.
The dollar has been reaching new lows against the euro and other key currencies since last summer, and was hit again on Friday by a US employment report showing the labour market at its weakest in five years.
This has prompted traders to seek refuge in commodities, including oil and gold, which are more likely to sustain their value than the greenback.
In Europe, Brent crude hit $104.42 at one point on Monday - also a record.
Financial strain
Analysts at the International Energy Agency said that real oil prices are higher than the previous peak reached in April 1980, which was $102.53 in today's money.
But the oil price measure used then was slightly different to the one in current use and so it is difficult to make an accurate comparison.
The high oil price is making petrol and energy costs more expensive around the world, putting financial pressure on businesses and household budgets.