Is this 1973 all over again?

Oil prices have more than tripled in 18 months, and the $40 barrel is now in sight. Are we looking at a 1973-style energy crisis?

It's like punk never happened, to quote from the phrasebook of music aficionados. Well, almost.

Angry farmers and lorry drivers are threatening widespread industrial action. In France there are long queues at petrol stations. And analysts fear inflation could drive economies into recession.

At the root of this unrest is the price of oil.

Over the past 18 months, the price of a barrel of oil has more than tripled to about $35. Political leaders, including the US president, Bill Clinton, are appealing to Opec (Organisation of Petroleum Exporting Countries) countries to boost production.

It is eerily reminiscent of the 1973 energy crisis when rising oil prices pushed up inflation and sent the world into an economic tailspin. Britain was hit particularly hard at the time, suffering power cuts, rampant inflation and a three-day working week.

As ministers from the 11 Opec nations prepare for a weekend debate on whether to increase oil production, the question is: are we heading for another oil crisis?

NO:

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The recent hike in oil prices came on the back of a sharp drop. Prices are still a third below their 1990 level, and half of that in 1981 - both times of previous economic slumps.

Oil is less important than it used to be. The shift in industrialised nations from manufacturing to service-based economies has reduced our dependence on oil.

Environmental concerns have led to more efficient use of oil and given rise to a wider range of energy sources, such as natural gas.

Accordingly, oil, and by-products such as petrol, are less of a dent on consumers' weekly spend. Today the average consumer spends 4.3p in every pound on oil-based fuel, compared to 10p in the early 1970s.

Britain's oil production has shot up since the 1970s

Opec has less of a stranglehold. It now accounts for only 44% of world production compared to 56% in the 70s. Britain has its presence, with North Sea oil, and the collapse of the Soviet Union has opened up new markets.

Additionally, Opec members seem to find it hard to stick to their quotas. Currently, they appear to be overproducing by 700,000 barrels a day.

Opec's action in 1973 was in retaliation to the West's backing of Israel against Arab nations. Hostilities in the Middle East have calmed significantly since then.

YES:

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Oil still drives economies. In August, the European Central Bank used its monthly bulletin to warn that oil prices were a key threat to its inflation target. The OECD (Organisation for Economic Cooperation and Development) says that after 12 months, a $10 rise in barrel price would lift inflation by half a percentage point and reduce growth by a quarter point.

Stocks of petrol, diesel and heating oil are historically low. In the West, oil stores stand at about 52 days - a week less than normal for this time of year. This is a particular problem in Germany and the US where heating oil is used to warm homes. How much these stocks are eaten into could depend on the severity of the forthcoming winter.

In 1973 we were facing the 50p gallon; now the £4 gallon looms

In the 1990s oil companies drew in the purse strings, cutting back on exploration budgets and development of existing fields. Latterly, the rise of the dotcom economy has overshadowed interest in oil companies.

Opec may not be able to produce much more oil even if wanted to. The International Energy Agency thinks Opec members are operating at 75-90% capacity, although demand is still growing. The exception is Saudi Arabia, which has plenty of spare capacity.

While industrialised countries have cut oil use since 1973, demand has shot up in the emerging economies of Asia and South America.