Transport inflation fell to 4.3% in October, from 7.6% in September.
This 3.3% point deceleration is the largest slow-down since CPI records began. It was triggered by a sharp fall in the price of crude oil.
The average price of petrol fell by 7.1p per litre between September and October this year, to stand at 104.5p, compared with a rise of 2.7p last year.
Diesel prices fell by 7p per litre this year, to stand at 116.3p. There was also a fall in the price of both air transport and sea transport.
The effect from air fares came mainly from the cost of European flights.
There was another large downward contribution from food and non-alcoholic
drinks.