Oil prices sank to their lowest level in three-and-a-half years, accumulating more than a $100 drop in less than five months, amid fresh concerns on Tuesday that the Opec oil cartel may not reduce its production level as much as it has promised.

The fall to Tuesday’s low of $46.82 a barrel from July’s record high of $147.27 has prompted a dramatic drop in wholesale costs for oil products such as petrol and heating oil. In New York, wholesale gasoline prices on Tuesday hit an intraday low just above the psychological $1-a-gallon level.